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

Commands tagged function from sorted by
Terminal - Commands tagged function - 102 results
calc() { bc <<< $*; }
calc() { python -c "from math import *; print $1"; }
2010-10-07 08:26:39
User: asmaier
Functions: python
1

This function defines a command line calculator that handles everything pythons math module can handle, e.g. trigonometric functions, sqrt, log, erf, ... (see http://docs.python.org/library/math.html). It even knows about the constants pi and e.

shout() { curl -s "http://shoutkey.com/new?url=${1}" | sed -n "/<h1>/s/.*href=\"\([^\"]*\)\".*/\1/p" ;}
shout () { curl -s "http://shoutkey.com/new?url=$1" | sed -n 's/\<h1\>/\&/p' | sed 's/<[^>]*>//g;/</N;//b' ;}
2010-10-04 23:50:54
User: elfreak
Functions: sed
4

Just add this function to your .zshrc / .bashrc, and by typing "shout *URL*" you get a randomly chosen English word that ShoutKey.com uses to short your URL. You may now go to shoutkey.com/*output_word* and get redirected. The URL will be valid for 5 minutes.

(I've never used sed before, so I'll be quite glad if someone could straighten up the sed commands and combine them (perhaps also removing the whitespace). If so, I'll update it right away ;) )

yt () mplayer -fs -quiet $(youtube-dl -g "$1")
2010-09-29 18:48:19
User: elfreak
15

A function for streaming youtube to mplayer.

The option "-g" for youtube-dl tells it to output the direct video URL, instead of downloading the video.

"-fs" tells MPlayer to go FullScreen, and "-quit" makes it less verbose.

Requires: youdube-dl ( http://bitbucket.org/rg3/youtube-dl/ )

(Tested in zsh)

eog `curl -s http://xkcd.com/ | sed -n 's/<h3>Image URL.*: \(.*\)<\/h3>/\1/p'`
xdg-open http://xkcd.com/
2010-08-25 19:14:11
-5

KISS

To get a random xkcd comic:

xdg-open http://dynamic.xkcd.com/random/comic/
xkcd() { wget -qO- http://xkcd.com/ | sed -n 's#^<img src="\(http://imgs.[^"]\+\)"\s\+title="\(.\+\?\)"\salt.\+$#eog "\1"\necho '"'\2'#p" | bash ; }
2010-08-25 15:44:31
User: John_W
Functions: bash sed wget
0

This function displays the latest comic from xkcd.com. One of the best things about xkcd is the title text when you hover over the comic, so this function also displays that after you close the comic.

To get a random xkcd comic use the following:

xkcdrandom() { wget -qO- http://dynamic.xkcd.com/comic/random | sed -n 's#^<img src="\(http://imgs.[^"]\+\)"\s\+title="\(.\+\?\)"\salt.\+$#eog "\1"\necho '"'\2'#p" | bash; }

These are just a bit shorter than the ones eigthmillion wrote, however his version didn't work as expected on my laptop for some reason (I got the title-tag first), so these build a command which is executed by bash.

eog `curl 'http://xkcd.com/' | awk -F "ng): |</h" '/embedding/{print $2}'`
gwenview `wget -O - http://xkcd.com/ | grep 'png' | grep '<img src="http://imgs.xkcd.com/comics/' | sed s/title=\".*//g | sed 's/.png\"/.png/g' | sed 's/<img src=\"//g'`
2010-08-24 22:21:51
User: hunterm
Functions: grep sed
-1

Output the html from xkcd's index.html, filter out the html tags, and then view it in gwenview.

s="StrinG"; echo ${s,,}
2010-08-12 16:02:38
User: karpoke
Functions: echo
Tags: bash function
3

Another alternative is to define a function:

lower() {

echo ${@,,}

}

lower StrinG

__disown(){ local cmd=$1 ; shift ; $cmd "$@" &> /dev/null &disown }; for i in gvim ; do alias $i="__disown $i"; done
2010-07-07 20:46:45
User: smolav
Functions: alias shift
Tags: bash function
0

Define commands that you always invoke with an appended '&disown'. In the example:

gvim foo.txt

will open gvim dettached from the current terminal.

L(){ l=`builtin printf %${2:-$COLUMNS}s` && echo -e "${l// /${1:-=}}"; }
2

One of the first functions programmers learn is how to print a line. This is my 100% bash builtin function to do it, which makes it as optimal as a function can be. The COLUMNS environment variable is also set by bash (including bash resetting its value when you resize your term) so its very efficient. I like pretty-output in my shells and have experimented with several ways to output a line the width of the screen using a minimal amount of code. This is like version 9,000 lol.

This function is what I use, though when using colors or other terminal features I create separate functions that call this one, since this is the lowest level type of function. It might be better named printl(), but since I use it so much it's more optimal to have the name contain less chars (both for my programming and for the internal workings).

If you do use terminal escapes this will reset to default.

tput sgr0

For implementation ideas, check my

http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

addman () { export MANPATH=`find $1 -xdev -type d -name man -printf %p:`${MANPATH}; }
2010-06-12 17:47:20
User: zoomgarden
Functions: export man
Tags: man function
0

Prepends paths containing man directories to your MANPATH variable for the given top level directory. If you build or install software with non-standard documentation locations, you can just add them to your MANPATH with this little function. -xdev prevents crossing filesystem boundaries when searching for man dirs.

quickfind () { find . -maxdepth 2 -iname "*$1*" }
2010-06-12 03:04:50
User: dbbolton
Functions: find
Tags: find function
1

A function that allows you to perform a case-insensitive search in the current directory, and directories in the current directory (but no further), for files containing the first argument anywhere in their names.

statt(){ C=c;stat --h|sed '/Th/,/NO/!d;/%/!d'|while read l;do p=${l/% */};[ $p == %Z ]&&C=fc&&echo ^FS:^;echo "`stat -$C $p \"$1\"` ^$p^${l#%* }";done|column -ts^; }
2010-06-11 23:31:03
User: AskApache
Functions: column read sed
3

This shows every bit of information that stat can get for any file, dir, fifo, etc. It's great because it also shows the format and explains it for each format option.

If you just want stat help, create this handy alias 'stath' to display all format options with explanations.

alias stath="stat --h|sed '/Th/,/NO/!d;/%/!d'"

To display on 2 lines:

( F=/etc/screenrc N=c IFS=$'\n'; for L in $(sed 's/%Z./%Z\n/'<<<`stat --h|sed -n '/^ *%/s/^ *%\(.\).*$/\1:%\1/p'`); do G=$(echo "stat -$N '$L' \"$F\""); eval $G; N=fc;done; )

For a similarly powerful stat-like function optimized for pretty output (and can sort by any field), check out the "lll" function

http://www.commandlinefu.com/commands/view/5815/advanced-ls-output-using-find-for-formattedsortable-file-stat-info

From my .bash_profile ->

http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'
7

I love this function because it tells me everything I want to know about files, more than stat, more than ls. It's very useful and infinitely expandable.

find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n' | sort -rgbS 50%

00761 drwxrw---x askapache:askapache 777:666 [06/10/10 | 06/10/10 | 06/10/10] [d] /web/cg/tmp

The key is:

# -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'

which believe it or not took me hundreds of tweaking before I was happy with the output.

You can easily use this within a function to do whatever you want.. This simple function works recursively if you call it with -r as an argument, and sorts by file permissions.

lsl(){ O="-maxdepth 1";sed -n '/-r/!Q1'<<<$@ &&O=;find $PWD $O -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -rgbS 50%; }

Personally I'm using this function because:

lll () { local a KS="1 -r -g"; sed -n '/-sort=/!Q1' <<< $@ && KS=`sed 's/.*-sort=\(.*\)/\1/g'<<<$@`; find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -k$KS -bS 50%; }

# i can sort by user

lll -sort=3

# or sort by group reversed

lll -sort=4 -r

# and sort by modification time

lll -sort=6

If anyone wants to help me make this function handle multiple dirs/files like ls, go for it and I would appreciate it.. Something very minimal would be awesome.. maybe like:

for a; do lll $a; done

Note this uses the latest version of GNU find built from source, easy to build from gnu ftp tarball. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

declare -F | cut -d ' ' -f 3
sortwc () { local L;while read -r L;do builtin printf "${#L}@%s\n" "$L";done|sort -n|sed -u 's/^[^@]*@//'; }
2010-05-20 20:13:52
User: AskApache
Functions: printf read sed sort
2

This provides a way to sort output based on the length of the line, so that shorter lines appear before longer lines. It's an addon to the sort that I've wanted for years, sometimes it's very useful. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

utime(){ python -c "import time; print(time.strftime('%a %b %d %H:%M:%S %Y', time.localtime($1)))"; }
utime(){ awk -v d=$1 'BEGIN{print strftime("%a %b %d %H:%M:%S %Y", d)}'; }
utime(){ date -d "1970-01-01 GMT $1 seconds"; }
utime { date -d @$1; }
2010-05-12 12:21:15
User: deltaray
Functions: date
4

More recent versions of the date command finally have the ability to decode the unix epoch time into a human readable date. This function makes it simple to utilize this feature quickly.

shmore(){ local l L M="`echo;tput setab 4&&tput setaf 7` --- SHMore --- `tput sgr0`";L=2;while read l;do echo "${l}";((L++));[[ "$L" == "${LINES:-80}" ]]&&{ L=2;read -p"$M" -u1;echo;};done;}
2010-04-21 00:40:37
User: AskApache
Functions: echo read
6
SH
cat mod_log_config.c | shmore

or

shmore < mod_log_config.c

Most pagers like less, more, most, and others require additional processes to be loaded, additional cpu time used, and if that wasn't bad enough, most of them modify the output in ways that can be undesirable.

What I wanted was a "more" pager that was basically the same as running:

cat file

Without modifying the output and without additional processes being created, cpu used, etc. Normally if you want to scroll the output of cat file without modifying the output I would have to scroll back my terminal or screen buffer because less modifies the output.

After looking over many examples ranging from builtin cat functions created for csh, zsh, ksh, sh, and bash from the 80's, 90s, and more recent examples shipped with bash 4, and after much trial and error, I finally came up with something that satisifed my objective. It automatically adjusts to the size of your terminal window by using the LINES variable (or 80 lines if that is empty) so

This is a great function that will work as long as your shell works, so it will work just find if you are booted in single user mode and your /usr/bin directory is missing (where less and other pagers can be). Using builtins like this is fantastic and is comparable to how busybox works, as long as your shell works this will work.

One caveat/note: I always have access to a color terminal, and I always setup both the termcap and the terminfo packages for color terminals (and/or ncurses and slang), so for that reason I stuck the

tput setab 4; tput setaf 7

command at the beginning of the function, so it only runs 1 time, and that causes the -- SHMore -- prompt to have a blue background and bright white text.

This is one of hundreds of functions I have in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html">.bash_profile at http://www.askapache.com/">AskApache.com, but actually won't be included till the next update.

If you can improve this in any way at all please let me know, I would be very grateful! ( Like one thing I want is to be able to continue to the next screen by pressing any key instead of now having to press enter to continue)