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I have been digging through my Linux system to try and understand how it all works.

In the /etc/crontab file I see the following:

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

What is run-parts, what does it do, and how can I use it?

1 Answer 1

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Basically, run-parts(8) takes a directory as an argument.

It will run every script that is found in this directory. For example, if you do a listing of /etc/cron.hourly, you'll see that it's a directory where you can put executable files to be run every hour.

As you can see, in cron it's used for convenience, since you only have to specify one directory and everything in that directory will be executed. This makes it easy to maintain scripts in one of the etc/cron* directories.

See its manpage for more options that could be exploited for your own use cases. You could for example do a simple check and show which scripts would be run:

run-parts -v --test /etc/cron.hourly

The -v flag might not be available everywhere.

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  • 1
    What is the root portion for?
    – Jake N
    Commented Nov 9, 2012 at 12:59
  • 1
    @jakenoble root means that the command (run-parts in this case) will be run as root user Commented Aug 30, 2013 at 9:36
  • 7
    Note that on CentOS (at least el5) run-parts is a bash script that doesn't have any options so you will get "-v is not a directory". Or at least that's what it shown me on my system.
    – Nux
    Commented Dec 17, 2013 at 14:03
  • CentOS probably got the idea from Debian but reimplemented it independently. There are many Linux distros which do not have this mechanism, too.
    – tripleee
    Commented Jan 12, 2023 at 10:24

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