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/
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.
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.
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:
I find it ugly & sexy at the same time isn't it ?
This command kills all processes with 'SomeCommand' in the process name. There are other more elegant ways to extract the process names from ps but they are hard to remember and not portable across platforms. Use this command with caution as you could accidentally kill other matching processes!
xargs is particularly handy in this case because it makes it easy to feed the process IDs to kill and it also ensures that you don't try to feed too many PIDs to kill at once and overflow the command-line buffer.
Note that if you are attempting to kill many thousands of runaway processes at once you should use 'kill -9'. Otherwise the system will try to bring each process into memory before killing it and you could run out of memory. Typically when you want to kill many processes at once it is because you are already in a low memory situation so if you don't 'kill -9' you will make things worse
This finds a process id by name, but without the extra grep that you usually see. Remember, awk can grep too!
Want to know why your load average is so high? Run this command to see what processes are on the run queue. Runnable processes have a status of "R", and commands waiting on I/O have a status of "D".
On some older versions of Linux may require -emo instead of -eo.
On Solaris: ps -aefL -o s -o user -o comm | egrep "^O|^R|COMMAND"
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1828 0.0 0.0 5396 476 ? Ss 2008 0:00 /usr/sbin/sshd
the $15 may change for you depending on your distro, etc...
This is a nice way to kill processes.. the example here is for firefox!!! substitute firefox for whatever the process name is...
Yet another ps grep function, but this one includes the column headings.
My variant on this common function. Some highlights:
Allows you to override the default ps args of "aux"
Uses bracket trick to omit the grep process itself without having to use a second grep
Always prints the correct header row of ps output
Limitations: Ugly ps error output if you forget to quote your multi word grep argument
This comes in handy if you have daemons/programs that have potential issues and stop/disappear, etc., can be run in cron to ensure that a program remains up no matter what. Be advised though, if a program did core out, you'd likely want to know why (gdb) so use with caution on production machines.
This is a 'killall' command equivalent where it is not available.
Prior to executing it, set the environment variable USERNAME to the username, whose processes you want to kill or replace the username with the $USERNAME on the command above.
Side effect: If any processes from other users, are running with a parameter of $USERNAME, they will be killed as well (assuming you are running this as root user)
[-9] in square brackets at the end of the command is optional and strongly suggested to be your last resort. I do not like to use it as the killed process leaves a lot of mess behind.
The trick here is to use the brackets [ ] around any one of the characters of the grep string. This uses the fact that [?] is a character class of one letter and will be removed when parsed by the shell. This is useful when you want to parse the output of grep or use the return value in an if-statement without having its own process causing it to erroneously return TRUE.
Useful to detect which process is causing system loads. It shows process PID so as we can take further actions.
This command is useful when you want to know what process is responsible for a certain GUI application and what command you need to issue to launch it in terminal.
while [ 1 -ne 6 ]; do
pid=`ps -ef | grep -v "grep" | grep "trans_gzdy" | cut -c10-17`
ps gv $pid | head -2
check changes of RSS.