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Oli
Asked: 2012-11-14 06:26:51 +0800 CST

Where is the user crontab stored?

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Since upgrading my user's crontab has been wiped out. This is not the first time this has happened this year and it's a pain restoring it each time.

I'd like to be able to back up the crontab for my user but for that I need to know where it's stored.

cron

4 Answers

  1. Best Answer

    Actually, it's not recommended to handle those files by hand. Per crontab man page:

    Each user can have their own crontab, and though
    these are files in /var/spool/cron/crontabs, they are not
    intended to be edited directly.

    Files under /var/spool are considered temporary/working, that's why they probably get deleted during an upgrade, though a closer look at the cron package's upgrade scripts may shed some light on this.

    Anyway, it's always a good practice to back up your cron entries or keep them in a file in your home directory.

    I assume you're using crontab -e to create crontab files on the fly. If so, you can get a "copy" of your crontab file by doing crontab -l. Pipe that to a file to get a "backup":

    crontab -l > my-crontab

    Then you can edit that my-crontab file to add or modify entries, and then "install" it by giving it to crontab:

    crontab my-crontab

    This does the same syntax checking as crontab -e.

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  2. Its stored inside /var/spool/cron/crontabs folder under username.

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  3. I finally found out why my crontabs and Postfix installation kept breaking after boot. It's a really stupid reason but...

    I had /var/spool mounted as a tmpfs RAM-drive.

    Sounds idiotic and it is, but I had followed one of the old SSD-tweaks to lengthen the life of my SSD. In doing so, I blindly mounted /tmp, /var/tmp and /var/spool as tmpfs without thinking of the repercussions. I thought /var/spool was like /proc/ or /run/ and that it was only useful for the duration of the session. I was clearly wrong.

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  4. To list all cron jobs from all users in your system:

    for user in $(cut -f1 -d: /etc/passwd)
do
  echo $user
  crontab -u $user -l
done

    An alternative to your issue would be to place them in cron.d folder and specify the appropriate user per cron as in example:

    00 01 * * * user /home/user/user-script.sh
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