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.

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

All commands

All commands from sorted by
Terminal - All commands - 9,165 results
curl -I -L http://t.co/mQUxL6yS
for a in $(< FILENAME); do echo "$(bc <<< $(wc -m<<<$a)-1) $a";done|sort -n
dng(){ local a;a=$(sed '/'"$1"'/!d' /etc/hosts |sed '=;'"${2-1,$}"'!d'|sed '/ /!d');echo $a|tr '\040' '\n'|nl -bp'[0-9]$'|less -E;export dn=$(echo $a|sed 's,.* ,,');export ip=$(echo $a|sed 's, .*,,');echo \$dn=$dn;echo \$ip=$ip;}
2012-04-01 23:57:09
User: argv
Functions: echo export less nl sed tr
0

usage: dng BRE [selection]

default selection is the last match

DNS is ok, but although domainnames may be easier to remember than IP numbers, it still requires typing them out. This can be error-prone. Even more so than typing IPv4 numbers, depending on the domainname, its length and complexity.

_p(){ ps ax |grep $1 |sed '/grep.'"$1"'/d' |while read a;do printf ${a%% *}' ';printf "${a#* }" >&2;printf '\n';done;}
2012-04-01 19:46:19
User: argv
Functions: grep printf ps read sed
0

proc lister

usage: p

proc killer

usage: p patt [signal]

uses only ps, grep, sed, printf and kill

no need for pgrep/pkill (not part of early UNIX)

_p(){

ps ax \

|grep $1 \

|sed '

/grep.'"$1"'/d' \

|while read a;do

printf ${a%% *}' ';

printf "${a#* }" >&2;

printf '\n';

done;

}

p(){

case $# in

0)

ps ax |grep .|less -iE;

;;

1)

_p $1;

;;

[23])

_p $1 2>/dev/null \

|sed '/'"$2"'/!d;

s,.*,kill -'"${3-15}"' &,'|sh -v

;;

esac;

}

alas, can't get this under 255 chars.

flatcap?

_p(){ ps ax |grep $1 |sed '/grep.'"$1"'/d' |while read a;do printf ${a%% *}' ';printf "${a#* }" >&2;printf '\n';done;}
2012-04-01 19:45:17
User: argv
Functions: grep printf ps read sed
0

proc lister

usage: p

proc killer

usage: p patt [signal]

uses only ps, grep, sed, printf and kill

no need for pgrep/pkill (not part of early UNIX)

_p(){

ps ax \

|grep $1 \

|sed '

/grep.'"$1"'/d' \

|while read a;do

printf ${a%% *}' ';

printf "${a#* }" >&2;

printf '\n';

done;

}

p(){

case $# in

0)

ps ax |grep .|less -iE;

;;

1)

_p $1;

;;

[23])

_p $1 2>/dev/null \

|sed '/'"$2"'/!d;

s,.*,kill -'"${3-15}"' &,'|sh -v

;;

esac;

}

alas, can't get this under 255 chars.

flatcap?

shopt -s autocd
2012-04-01 14:34:29
User: stubby
15

In bash, this turns on auto cd. If a command is just a directory name, it cd's into that directory.

alias b='cd ../'
2012-04-01 06:04:45
User: deshawnbw
Functions: alias
Tags: alias
2

Alias a single character 'b' to move to parent directory. Put it into your .bashrc or .profile file.

Using "cd .." is one of the most repetitive sequence of characters you'll in the command line. Bring it down to two keys 'b' and 'enter'.

It stands for "back"

Also useful to have multiple:

alias b='cd ../'

alias bb='cd ../../'

alias bbb='cd ../../../'

alias bbbb='cd ../../../../'

find /some/path -type f -and -iregex '.*\.mp3$' -and -print0 | tr -d -c '\000' |wc -c
2012-03-31 21:57:33
User: kyle0r
Functions: find tr wc
0

In this example, the command will recursively find files (-type f) under /some/path, where the path ends in .mp3, case insensitive (-iregex).

It will then output a single line of output (-print0), with results terminated by a the null character (octal 000). Suitable for piping to xargs -0. This type of output avoids issues with garbage in paths, like unclosed quotes.

The tr command then strips away everything but the null chars, finally piping to wc -c, to get a character count.

I have found this very useful, to verify one is getting the right number of before you actually process the results through xargs or similar. Yes, one can issue the find without the -print0 and use wc -l, however if you want to be 1000% sure your find command is giving you the expected number of results, this is a simple way to check.

The approach can be made in to a function and then included in .bashrc or similar. e.g.

count_chars() { tr -d -c "$1" | wc -c; }

In this form it provides a versatile character counter of text streams :)

sh time.sh 1 20 & var1="$!" & sh time.sh 2 10 & var2="$!" & sh time.sh 3 40 & var3="$!" & sh time.sh 4 30 & var4="$!" ; wait $var1 && wait $var2 && wait $var3 && wait $var4
2012-03-31 10:03:58
User: julnegre
Functions: sh wait
0

This command explains how to manage some asynchronous PID in a global process.

The command uses 4 processes in a global process. The asynchronous scripts are simulated by a time.sh script

more infos :

http://code-esperluette.blogspot.fr/2012/03/bash-gestion-de-processus-asynchrones.html

http://www.youtube.com/watch?v=TxsPyAtD70I

curl ifconfig.me
2012-03-30 22:04:58
User: bkozumplik
1

It's easier then the listed command, I'm thinking. but doesn't matter much--its closer to personal preference really.

find . -type f -print0 | xargs -0 du -h | sort -hr | head -20
2012-03-30 10:21:12
User: flatcap
Functions: du find head sort xargs
6

Search for files and list the 20 largest.

find . -type f

gives us a list of file, recursively, starting from here (.)

-print0 | xargs -0 du -h

separate the names of files with NULL characters, so we're not confused by spaces

then xargs run the du command to find their size (in human-readable form -- 64M not 64123456)

| sort -hr

use sort to arrange the list in size order. sort -h knows that 1M is bigger than 9K

| head -20

finally only select the top twenty out of the list

find . -mount -type f -printf "%k %p\n" | sort -rg | cut -d \ -f 2- | xargs -I {} du -sh {} | less
scanelf --nobanner --recursive --quiet --needed --format "+n#F" $1 | tr ',' '\n' | sort -u
2012-03-29 18:30:45
User: Flameeyes
Functions: sort tr
0

This works in combination with http://www.commandlinefu.com/commands/view/10496/identify-exported-sonames-in-a-path as it reports the NEEDED entries present in the files within a given path. You can then compare it with the libraries that are exported to make sure that, when cross-building a firmware image, you're not bringing in dependencies from the build host.

The short version of it as can be seen in the same output is

scanelf -RBnq -F "+n#f" $1 | tr ',' '\n' | sort -u
scanelf --nobanner --recursive --quiet --soname --format "+S#f"
2012-03-29 18:26:25
User: Flameeyes
0

This provides a list of shared object names (sonames) that are exported by a given tree. This is usually useful to make sure that a given required dependency (NEEDED entry) is present in a firmware image tree.

The shorter (usable) version for it would be

scanelf -RBSq -F "+S#f"

But I used the verbose parameters in the command above, for explanation.

apt-get -s upgrade | awk '/[0-9]+ upgraded,/ {print $1 " package updates are available"}'
2012-03-29 17:04:32
User: lpanebr
Functions: apt awk
2

This let's you find out the total packages that have available upgrades. Usefull if you want to check or show the total available upgrades on your system.

alias man='man -S 2:3:1'
pdftk A=1.pdf B=2.pdf C=3.pdf cat C A output CA.pdf
pdftk 1.pdf 2.pdf cat output 12.pdf
pdfinfo file.pdf | grep "^Pages: *[0-9]\+$" | sed 's/.* //'
pdftk file.pdf dump_data output | grep -i Num
sudo dpkg-reconfigure keyboard-configuration
2012-03-27 21:07:45
Functions: sudo
0

Bash snippet to force GNU/Linux keyboard settings, layout and configuration.

Usefull when some GNU/Linux distributions such as *Ubuntu's store only limited configation options due to demonstration purposes on LiveUSB or Live persistent devices.

Overcomes the English QWERTY to French AZERTY settings failure.

Code bash en ligne de commande pour forcer l'adoption du clavier AZERTY sur les cl? USB bootable en Ubuntu.

timeout -k 1m 30s some_command
2012-03-27 18:06:18
User: tlemerond
Tags: fg bg kill timeout
1

A timeout is great, but what if the command is taking longer than expected because it's hung up or ran into some other problem? That's where the -k option comes in. Run "some_command" and timeout after 30s. If the command is still running after 1 minute, it will receive a kill signal.

lsb_release -a
cat > file_name
2012-03-27 11:38:09
Functions: cat
-2

Write script or commands in notepad/Editplus/MS word etc, copy the contents, type the above command and click on enter now, paste by right click-ing the mouse. Entire contents in the clip-board gets pasted now again click on Enter to go to new line/next line. Press Ctrl+D to close/save the file. Not always required to vi to create a new file.

svnll(){svn log "$@"|( read; while true; do read h||break; read; m=""; while read l; do echo "$l" | grep -q '^[-]\+$'&&break; [ -z "$m" ] && m=$l; done; echo "$h % $m" | sed 's#\(.*\) | \(.*\) | \([-0-9 :]\{16\}\).* % \(.*\)#\1 \2 (\3) \4#'; done)}
2012-03-25 20:39:05
User: vhotspur
Functions: echo grep read sed
Tags: log subversion
0

Emulate (more or less) Git equivalent of

git log --format='tformat:%h %an (%cr) %s'