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 using env from sorted by
Terminal - Commands using env - 11 results
env PS4=' ${BASH_SOURCE:-0$}:${LINENO}(${FUNCNAME[0]}) ' sh -x /etc/profile
cat /dev/urandom | env LC_CTYPE=C tr -dc a-zA-Z0-9 | head -c 16; echo
2014-02-05 15:04:07
User: yakovlev
Functions: cat env head tr
0

Feel free to put this in your ~/.profile:

random(){ cat /dev/urandom | env LC_CTYPE=C tr -dc $1 | head -c $2; echo; }

Then use it to generate passwords:

random [:alnum:] 16

Or DNA sequences:

random ACGT 256
hl-nonprinting () { local C=$(printf '\033[0;36m') B=$(printf '\033[0;46m') R=$(printf '\033[0m') np=$(env printf "\u00A0\uFEFF"); sed -e "s/\t/${C}▹&$R/g" -e "s/$/${C}⁋$R/" -e "s/[$np]/${B}& $R/g";}
2012-11-07 10:09:40
User: unhammer
Functions: env printf sed
-1

Can't see it here, but the non-breaking space is highlighted :)

Of course,

cat -t -e

achieves something similar, but less colourful.

Could add more code points from https://en.wikipedia.org/wiki/Space_%28punctuation%29#Spaces_in_Unicode

10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 | grep '1 received' - || env DISPLAY=:0 xeyes
2012-02-06 09:40:11
User: knoppix5
Functions: env grep ping
Tags: ping host crontab
-2

Every 20 minutes ping host with IP address 192.168.0.14. If it's not 'alive' or not reachable, then display something eye-catching (here xeyes) on the desktop.

Hint for newbies: edit crontab with

crontab -e
sudo env ARCHFLAGS="-arch x86_64" gem install mysql
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
0

Prepending

env LC_CTYPE=C

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

set env DYLD_INSERT_LIBRARIES = /usr/lib/libgmalloc.dylib;b szone_error
2010-10-13 20:25:48
User: frank514
Functions: env set
0

setting gdb with this option / breakpoint before running the process will cause it to break whenever an memory allocation operation is not kosher.

sh -c 'if pgrep x2vnc && env LC_ALL=C xmessage -button "Kill it:0,Ignore it:1" "Another connection is already running. Should I kill it instead of ignoring it?"; then killall x2vnc; fi; x2vnc -passwd /home/Ariel/.vnc/passwd -east emerson:0'
2010-07-06 09:11:12
User: zhangweiwu
Functions: env killall sh
0

This command is suitable to use as application launching command for a desktop shortcut. It checks if the application is already running by pgrepping its process ID, and offer user to kill the old process before starting a new one.

It is useful for a few x11 application that, if re-run, is more likely a mistake. In my example, x2vnc is an x11 app that does not quit when its connection is broken, and would not work well when a second process establish a second connection after the first broken one.

The LC_ALL=C for xmesseng is necessary for OpenSUSE systems to avoid a bug. If you don't find needing it, remove the "env LC_ALL=C" part

alias rc='ssh ${MEDIAPCHOSTNAME} env DISPLAY=:0.0 rhythmbox-client --no-start'
2010-01-17 19:43:43
User: rhythmx
Functions: alias env
9

Note: you'll want to set up pub-key ssh auth. Gives you a quick means of changing volume/tracks/etc for rhythmbox on a remote machine. E.g.:

rc --next # Play next track

rc --print-playing # Grab the name

rc --volume-down

rc --help

env PS4=' ${BASH_SOURCE}:${LINENO}(${FUNCNAME[0]}) ' sh -x /etc/profile
find . -type d -exec env d="$dest_root" sh -c ' exec mkdir -p -- "$d/$1"' '{}' '{}' \;