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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
Up
Down
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.

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Alternatives

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Terminal - Alternatives

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What others think

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

Comment by jxy 205 weeks and 4 days ago

I use while true to make neverending loops with while.

Comment by b2e 205 weeks and 4 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 205 weeks and 3 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 205 weeks and 3 days ago

Could use incron for that purpose rhythmx.

Comment by DaveQB 205 weeks and 1 day ago

you can avoid while true:

chronic () { t=$1; shift; while sleep $t; do $@; done & }
Comment by glaudiston 146 weeks and 1 day ago

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

while sleep ; do ; done &

Comment by glaudiston 146 weeks and 1 day ago

the command above was modified by site:

while sleep <you time>; do <your command>; done;
Comment by glaudiston 146 weeks and 1 day ago

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