Commands by alset (1)

What's this?

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

Share Your Commands


Check These Out

Empty a file
Immediately make a file empty. This even works if the file is still being written to. Great for cleaning up huge log files!

ssh autocomplete based on ~/.ssh/config
I use this in my bashrc to expand hosts defined in ~/.ssh/config: function _ssh_completion() { perl -ne 'print "$1 " if /^Host (.+)$/' ~/.ssh/config } complete -W "$(_ssh_completion)" ssh Here's a great article on how to setup your own ~/.ssh/config: http://blogs.perl.org/users/smylers/2011/08/ssh-productivity-tips.html

Piping Microphone Audio Over Netcat
Send microphone audio to another computer using netcat and arecord. Connect to the stream using "nc [other ip] 3333|aplay" You can set up two-way communication by piping audio the reverse direction on another port: Machine #1: $arecord -D hw:0,0 -f S16_LE -c2|nc -l 3333 &;nc -l 3334|aplay Machine #2: $$ip=[machine1_ip];arecord -D hw:0,0 -f S16_LE -c2|nc $ip 3334 &;nc $ip 3333|aplay

Convert PNG to GIF
(relies on 'imagemagick') Convert all .png files to .gif. This can also go the other way if you reverse the file extensions in the command, e.g.: $ for file in *.gif; do convert "$file" "$(basename $file .gif).png"; done If the file is named 'example1.png' it will be named 'example1.gif' when it is complete.

Download all images from a website in a single folder

List processes playing sound
When trying to play a sound you may sometimes get an error saying that your sound card is already used, but not by what process. This will list all processes playing sound, useful to kill processes that you no longer need but that keep using your sound card.

Mount proc
Run this in / in a chroot to get your own proc there.

delete unversioned files in a checkout from svn

Top 10 Memory Processes (reduced output to applications and %usage only)
Top 10 Memory Processes (reduced output to applications and %usage only)

Show the power of the home row on the Dvorak Keyboard layout
Quick and dirty command that counts how many words can be typed just using the home row on the Dvorak Simplified Keyboard layout from a dictionary file, in this case /usr/share/dict/words. According to the regular expression supplied, each word must contain all the keys on the Dvorak home row, and no other characters. For comparison, I've shown how many words are installed in my dictionary, how many can be typed with just the Dvorak home row and how many can be typed with just the QWERTY home row in the sample output. Nearly 10 times the amount. If you want to see the words, remove the -c switch, and each word will be printed out.


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: