All commands (13,991)

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

Lists all listening ports together with the PID of the associated process
The PID will only be printed if you're holding a root equivalent ID.

Complex string encoding with sed
Pipe | avoid escaping occurences problems in using sed and make it easier to use

Find the package that installed a command

Replicate a directory structure dropping the files

Remote screenshot
Say if you're logged into a remote system via ssh and this system has an x window system, but yet you still want a screen shot of what's going on graphically. This will do it for you. :-)

list files recursively by size

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

delay execution of a command that needs lots of memory and CPU time until the resources are available
[ 2000 -ge "$(free -m | awk '/buffers.cache:/ {print $4}')" ] returns true if less than 2000 MB of RAM are available, so adjust this number to your needs. [ $(echo "$(uptime | awk '{print $10}' | sed -e 's/,$//' -e 's/,/./') >= $(grep -c ^processor /proc/cpuinfo)" | bc) -eq 1 ] returns true if the current machine load is at least equal to the number of CPUs. If either of the tests returns true we wait 10 seconds and check again. If both tests return false, i.e. 2GB are available and machine load falls below number of CPUs, we start our command and save it's output in a text file. The ( ( ... ) & ) construct lets the command run in background even if we log out. See http://www.commandlinefu.com/commands/view/3115/ .

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Make redirects to localhost via /etc/hosts more interesting
Normally when a site is blocked through /etc/hosts, traffic is just being redirected to a non-existent server that isn't going to respond. This helps get your point across a little more clearly than a browser timeout. Of course you could use any number of codes: http://en.wikipedia.org/wiki/List_of_HTTP_status_codes Obviously, this command can be added to init-rc.d, and more sophisticated responses can be given. Seems noteworthy to mention that the information sent from the browser can be parsed using the bash READ builtin (such as 'while read -t 1 statement; do parsing'), and the connection stays open until the script exits. Take care that you must use EXEC:'bash -c foo.sh', as 'execvp' (socat's method for executing scripts) invokes 'sh', not 'bash'.


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: