Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

OpenID
or
Sign in Register

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Hide

Credits

Site by David Winterbottom (user root).

Commands using head

Commands using head from sorted by
Terminal - Commands using head - 194 results
env LC_CTYPE=C tr -dc "a-zA-Z0-9-_\$\?" < /dev/urandom | head -c 10
2011-02-22 17:09:44
User: aerickson
Functions: env head tr
Tags: password random generate mac os x
0
Up
Down
generate random password (works on Mac OS X)

Prepending

env LC_CTYPE=C

fixes a problem with bad bytes in /dev/urandom on Mac OS X

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
nice -n 5 electricsheep -window-id `xwininfo -root|head -n 2|grep xwininfo|cut -c 22-26`
2011-02-14 03:58:58
User: kbaegis
Functions: cut grep head nice
0
Up
Down
Animated Desktop: electricsheep

This is a simple command which makes electricsheep render directly to your background

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -type f -name '*.pm' -printf '%6s %p\n' | sort -nr | head -n 50
2011-02-09 16:19:11
User: depesz
Functions: find head sort
0
Up
Down
List 50 largest source files in a project

Will work with filenames with spaces inside. Will not break in case of someone making directory that matches *.pm. And sorts from largest. Where largest is file size, not line count.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl http://www.discogs.com/search?q=724349691704 2> /dev/null | grep \/release\/ | head -2 | tail -1 | sed -e 's/^<div>.*>\(.*\)<\/a><\/div>/\1/'
2011-01-30 23:45:50
User: mrman
Functions: grep head sed tail
Tags: sed grep curl discogs UPC
0
Up
Down
Find artist and title of a music cd, UPC code given (first result only)

Changed wget to curl and it doesn't create a file anymore.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
wget http://www.discogs.com/search?q=724349691704 -O foobar &> /dev/null ; grep \/release\/ foobar | head -2 | tail -1 | sed -e 's/^<div>.*>\(.*\)<\/a><\/div>/\1/' ; rm foobar
2011-01-30 23:34:54
User: TetsuyO
Functions: grep head rm sed tail wget
Tags: sed wget grep discogs UPC
-1
Up
Down
Find artist and title of a music cd, UPC code given (first result only)

Substitute that 724349691704 with an UPC of a CD you have at hand, and (hopefully) this oneliner should return the $Artist - $Title, querying discogs.com.

Yes, I know, all that head/tail/grep crap can be improved with a single sed command, feel free to send "patches" :D

Enjoy!

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
while true; do lynx --dump http://whatthecommit.com/ | head -n 1 | cowsay; sleep 2; done
2011-01-27 14:36:12
User: linuxswords
Functions: head sleep
4
Up
Down
let the cow suggest some commit messages for you
Comments (6) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl -s http://www.last.fm/user/$LASTFMUSER | grep -A 1 subjectCell | sed -e 's#<[^>]*>##g' | head -n2 | tail -n1 | sed 's/^[[:space:]]*//g'
2011-01-24 08:16:48
User: sn0opy
Functions: grep head sed tail
Tags: sed tail grep HEAD last.fm
-1
Up
Down
Fetch current song from last.fm
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ls -S|head -1find
2011-01-15 10:20:31
User: liyuance
Functions: head ls
1
Up
Down
find the biggest file in current folder
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
finger | grep $(whoami) | head -n1 | awk '{print $2 " " $3}'
2011-01-07 16:54:11
User: mogoh
Functions: awk finger grep head
0
Up
Down
Prints out, what the users name, notifyed in the gecos field, is

finger - gets logged in users

grep $(whoami) - greps only the current user (if there are more logged in)

head -n1 - just one line

awk '{print $2 " " $3}' - second and third word, seperated with a space (the users name)

OT: My first commandlinefu-command :)

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
seq -w 50 | sort -R | head -6 |fmt|tr " " "-"
2011-01-05 01:12:58
User: metalx1000
Functions: head seq sort tr
Tags: random range shuf
0
Up
Down
lotto generator
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find -type f | xargs -I{} du -s "{}" | sort -rn | head | cut -f2 | xargs -I{} du -sh "{}"
2011-01-04 11:10:56
User: glaudiston
Functions: cut du find head sort xargs
Tags: size find filesize
0
Up
Down
Find the biggest files

Show the top file size in human readable form

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
head -100000 /dev/urandom | strings|tr '[A-Z]' '[a-z]'|sort >temp.txt && wget -q http://www.mavi1.org/web_security/wordlists/webster-dictionary.txt -O-|tr '[A-Z]' '[a-z]'|sort >temp2.txt&&comm -12 temp.txt temp2.txt
2010-12-26 11:04:42
User: marssi
Functions: head sort tr wget
6
Up
Down
Look for English words in /dev/urandom

Little faster alternative.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
head -100000 /dev/urandom | strings > temp.txt && for w in $(cat webster-dictionary.txt); do if [ ${#w} -gt 3 ]; then grep -io $w temp.txt; fi; done
2010-12-23 01:58:56
User: rugina
Functions: cat grep head strings
6
Up
Down
Look for English words in /dev/urandom

* to get the English dictionary: wget http://www.mavi1.org/web_security/wordlists/webster-dictionary.txt

Show sample output | Comments (3) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
(netstat -atn | awk '{printf "%s\n%s\n", $4, $4}' | grep -oE '[0-9]*$'; seq 32768 61000) | sort -n | uniq -u | head -n 1
2010-12-15 09:27:59
User: depesz
Functions: awk grep head netstat seq sort uniq
2
Up
Down
find an unused unprivileged TCP port

perl-less way

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
function where(){ COUNT=0; while [ `where_arg $1~$COUNT | wc -w` == 0 ]; do let COUNT=COUNT+1; done; echo "$1 is ahead of "; where_arg $1~$COUNT; echo "by $COUNT commits";};function where_arg(){ git log $@ --decorate -1 | head -n1 | cut -d ' ' -f3- ;}
2010-12-08 15:41:39
User: noisy
Functions: cut echo head wc
Tags: git
0
Up
Down
telling you from where your commit come from

usage:

where COMMIT

for instance:

where 1178c5950d321a8c5cd8294cd67535157e296554

where HEAD~5

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo `cat /dev/urandom | base64 | tr -dc "[:alnum:]" | head -c64`
2010-12-06 21:04:57
User: Dereckson
Functions: echo head tr
-1
Up
Down
create random string from /dev/urandom (or another length)

The same command, but with a base64 filter, more forgiving for special characters than tr.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo `cat /dev/urandom |tr -dc "[:alnum:]" | head -c64`
2010-12-06 20:01:56
User: unixmonkey14859
Functions: echo head tr
1
Up
Down
create random string from /dev/urandom (or another length)
Comments (5) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
( apache2ctl -t && service apache2 restart || (l=$(apache2ctl -t 2>&1|head -n1|sed 's/.*line\s\([0-9]*\).*/\1/'); vim +$l $(locate apache2.conf | head -n1)))
2010-11-26 18:12:08
User: cicatriz
Functions: head locate sed vim
Tags: apache apache2 services
3
Up
Down
Check apache config syntax and restart or edit the file

Checks the apache configuration syntax, if is OK then restart the service otherwise opens the configuration file with VIM on the line where the configuration fails.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ps ax -L -o pid,tid,psr,pcpu,args | sort -nr -k4| head -15 | cut -c 1-90
2010-11-17 01:04:31
User: strzel_a
Functions: cut head ps sort
1
Up
Down
Show CPU usage for EACH cores
Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -type f -newer 201011151300.txt -exec head -1 {} \;
2010-11-15 22:51:13
User: abm2009
Functions: find head
0
Up
Down
print the first line of every file which is newer than a certain date and in the current directory

create the "newer than" file by:

touch -t 201011151300 ./201011151300.txt

the format for the time is

[[CC]YY]MMDDhhmm[.SS]

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
head -n 20 <filename> | tail
2010-11-15 13:08:12
User: jamolkhon
Functions: head
-6
Up
Down
Print all the lines between 10 and 20 of a file
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl -s -O http://s3.amazonaws.com/alexa-static/top-1m.csv.zip ; unzip -q -o top-1m.csv.zip top-1m.csv ; head -1000 top-1m.csv | cut -d, -f2 | cut -d/ -f1 > topsites.txt
2010-11-01 01:25:53
User: chrismccoy
Functions: cut head
Tags: curl unzip cut
-4
Up
Down
get a list of top 1000 sites from alexa

this will dump a list of domains one per line into a text file

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
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 ;}
2010-10-16 05:50:32
User: elfreak
Functions: echo grep head mkdir tar wc
Tags: bash tar function zsh tarbomb
10
Up
Down
Escape potential tarbombs

This Anti-TarBomb function makes it easy to unpack a .tar.gz without worrying about the possibility that it will "explode" in your current directory. I've usually always created a temporary folder in which I extracted the tarball first, but I got tired of having to reorganize the files afterwards. Just add this function to your .zshrc / .bashrc and use it like this;

atb arch1.tar.gz

and it will create a folder for the extracted files, if they aren't already in a single folder.

This only works for .tar.gz, but it's very easy to edit the function to suit your needs, if you want to extract .tgz, .tar.bz2 or just .tar.

More info about tarbombs at http://www.linfo.org/tarbomb.html

Tested in zsh and bash.

UPDATE: This function works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in zsh (not working in bash):

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%.t(ar.gz||ar.bz2||gz||bz||ar)} && tar xf $1 -C ${1%.t(ar.gz||ar.bz2||gz||bz||ar)}; fi ;}

UPDATE2: From the comments; bepaald came with a variant that works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in bash:

atb() {shopt -s extglob ; 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%.t@(ar.gz|ar.bz2|gz|bz|ar)} && tar xf $1 -C ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)}; fi ; shopt -u extglob}
Show sample output | Comments (5) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
svn log --stop-on-copy | grep r[0-9] | awk '{print $1}' | sed "s/r//" | sort -n | head -1
2010-10-07 21:21:20
User: jimthunderbird
Functions: awk grep head sed sort
-1
Up
Down
Get the revision number at which the current branch is created.
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl --silent http://www.dudalibre.com/gnulinuxcounter?lang=en | grep users | head -2 | tail -1 | sed 's/.*<strong>//g' | sed 's/<\/strong>.*//g'
2010-10-07 04:12:45
User: hunterm
Functions: grep head sed tail users
0
Up
Down
Get the amount of users currently registered at the DudaLibre.com Linux Counter.
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate