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.

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:

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

Tags

Hide

Functions

The Chronic: run a command every N seconds in the background

Terminal - The Chronic: run a command every N seconds in the background
chronic () { t=$1; shift; while true; do $@; sleep $t; done & }
2009-06-13 05:57:54
User: rhythmx
Functions: sleep
3
The Chronic: run a command every N seconds in the background

Chronic Bash function:

chronic 3600 time # Print the time in your shell every hour chronic 60 updatedb > /dev/null # update slocate every minute

Note: use 'jobs' to list background tasks and fg/bg to take control of them.

Alternatives

There are 6 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

Crontab/at commands would be better, if you have the rights to use them.

Comment by jxy 275 weeks and 2 days ago

I use while true to make neverending loops with while.

Comment by b2e 275 weeks and 2 days ago

In case you want it as a foreground process, this is exactly what 'watch' is for. watch repeatedly executes a command at a user-specified interval and displays the results. I agree with the others, if you make it a background process, you might as well automate it with cron.

Comment by bwoodacre 275 weeks and 2 days ago

Doh.. totally forgot about `watch'. Anyway running things in a term as opposed to cron can have distinct advantages. The command will only ever run as long as your session, and you'll get all of your environment vars automatically (e.g. DISPLAY).

I just pasted that from my new shiny .xinitrc for fluxbox, it watches for mtime updates to my wallpaper JPEG and automatically updates the rootbg when it changes.

Comment by rhythmx 275 weeks and 2 days ago

Could use incron for that purpose rhythmx.

Comment by DaveQB 275 weeks ago

you can avoid while true:

chronic () { t=$1; shift; while sleep $t; do $@; done & }
Comment by glaudiston 216 weeks ago

or better, if you want it, do not need to do a function, use while directly:

while sleep ; do ; done &

Comment by glaudiston 215 weeks and 6 days ago

the command above was modified by site:

while sleep <you time>; do <your command>; done;
Comment by glaudiston 215 weeks and 6 days ago

Your point of view

You must be signed in to comment.

Related sites and podcasts