All commands (14,187)

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

Triple monitoring in screen
This command starts screen with 'htop', 'nethogs' and 'iotop' in split-screen. You have to have these three commands (of course) and specify the interface for nethogs - mine is wlan0, I could have acquired the interface from the default route extending the command but this way is simpler. htop is a wonderful top replacement with many interactive commands and configuration options. nethogs is a program which tells which processes are using the most bandwidth. iotop tells which processes are using the most I/O. The command creates a temporary "screenrc" file which it uses for doing the triple-monitoring. You can see several examples of screenrc files here: http://www.softpanorama.org/Utilities/Screen/screenrc_examples.shtml

record the input of your sound card into ogg file
save the input into a ogg file

floating point operations in shell scripts
using bc is for sissies. dc is much better :-D Polish notation will rule the world...

do something else while waiting for an event, such as reboot
until (ssh root@10.1.1.39 2> /dev/null); do date; sleep 15; done In this case will execute "date" then "sleep 15" until we are able to ssh into server, such as after a reboot Could also be like: until ( ping 10.1.1.39 1> /dev/null); do echo "server 10.1.1.39 is down"; sleep 15; done

Check the hard disk vendor and model on Apple Mac

a find and replace within text-based files, for batch text replacement, not using perl
Use sed to edit in-place a list of files returned by find.

small CPU benchmark with PI, bc and time.
$ # 4 cores with 2500 pi digits $ CPUBENCH 4 2500 $. $ every core will use 100% cpu and you can see how fast they calculate it. $ if you do 50000 digitits and more it can take hours or days

Check if system is 32bit or 64bit
Needed a quick way to see if my server distro that I setup years ago was running 32bit or not, since with time I had forgotten. Note: does not check _hardware_ e.g. /proc/cpuinfo but rather the kernel installed

Shows what processes need to be restarted after system upgrade
emerge,apt-get,yum... all update your system. This will at some point replace either a runtime dependency or a process (which is still running). This oneliner will list what processes need to be restarted

Coping files, excluding certain files
Preserve file structure when coping and exclude some file o dir patterns


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: