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.

OpenID

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:

» all commands
» commands with 3 up-votes (commandlinefu3)
» commands with 10 up-votes (commandlinefu10)
» commands by px

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

Functions

Hide

Credits

Site by David Winterbottom (user root).

Commands by px

Terminal - Commands by px - 3 results

ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace

This is sample output - yours may be different.

ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace
Process 7313 attached - interrupt to quit
Process 7395 attached - interrupt to quit
Process 7396 attached - interrupt to quit
Process 7397 attached - interrupt to quit
Process 7398 attached - interrupt to quit
Process 7399 attached - interrupt to quit
Process 7401 attached - interrupt to quit
Process 7403 attached - interrupt to quit
Process 7448 attached - interrupt to quit
Process 7468 attached - interrupt to quit
Process 7469 attached - interrupt to quit
attach: ptrace(PTRACE_ATTACH, ...): No such process
[pid  7313] select(0, NULL, NULL, NULL, {0, 48000} <unfinished ...>
[pid  7395] poll([{fd=11, events=POLLIN}, {fd=10, events=POLLIN}, {fd=9, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=6, events=POLLIN}, {fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=85, events=POLLIN}, {fd=19, events=POLLIN}], 10, -1 <unfinished ...>
[pid  7396] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7397] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7398] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7399] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7401] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7403] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7448] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7468] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7469] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7313] <... select resumed> )      = 0 (Timeout)
[pid  7313] gettimeofday({1300139401, 36665}, NULL) = 0
[pid  7313] waitpid(-1, 0xffdc0a68, WNOHANG|WSTOPPED) = 0
[pid  7313] select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
[pid  7313] gettimeofday({1300139402, 39688}, NULL) = 0
[pid  7313] waitpid(-1, 0xffdc0a68, WNOHANG|WSTOPPED) = 0
[pid  7313] select(0, NULL, NULL, NULL, {1, 0} <unfinished ...>
Process 7313 detached
Process 7395 detached
Process 7396 detached
Process 7397 detached
Process 7398 detached
Process 7399 detached
Process 7401 detached
Process 7403 detached
Process 7448 detached
Process 7468 detached
Process 7469 detached

2011-03-14 21:45:22

User: px

Functions: awk grep ps xargs

Tags: awk token ps tokenizer

Up
Down

easily strace all your apache processes

This one-liner will use strace to attach to all of the currently running apache processes output and piped from the initial "ps auxw" command into some awk.

( di $TOFSCK -h ; /bin/umount $TOFSCK ; time /sbin/e2fsck -y -f -v $FSCKDEV ; /bin/mount $TOFSCK ) |& /bin/mail $MAILTO -s "$MAILSUB"

2010-10-24 00:35:23

User: px

Functions: time

Tags: Filesystem mount mount point size file cronjob automation check automatically crontab

Up
Down

Easy to extend one-liner for cron scripts that automate filesystem checking

This one-liner is for cron jobs that need to provide some basic information about a filesystem and the time it takes to complete the operation. You can swap out the di command for df or du if that's your thing. The |& redirections the stderr and stdout to the mail command.

How to configure the variables.

TOFSCK=/path/to/mount

FSCKDEV=/dev/path/device

FSCKDEV=`grep $TOFSCK /proc/mounts | cut -f1 -d" "`

MAILSUB="weekly file system check $TOFSCK "

screen /dev/tty<device> 9600

2010-07-20 09:12:13

User: px

Functions: screen

Tags: screen terminal serial console emulator terminal emulator,

Up
Down

use screen as a terminal emulator to connect to serial consoles