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I would like to run a cron job as a specific user on my machine. How may I specify the user for a cron job to run as?.

The cron jobs will be running on a server (running on Ubuntu 10.0.4). The 'users' are users that have been created specifically for carrying out specific server side tasks. These 'users' have the following in common:

  • Cannot log onto the system
  • Have restricted access to specific folders/files
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4 Answers 4

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96

Assuming you can't just log in and add it to that user's crontab, put a file in /etc/cron.d. It should be formatted as a normal cronjob, but with an extra field. Before the command to run and after the timing, put the user. You should be able to find examples already on your system.

Example:

#<timing>   <user> <command>
11 * * * *  root   /usr/lib/command
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3
  • I think this is the correct answer. I will have to look for some examples and investigate some more.
    – morpheous
    Aug 2, 2010 at 12:19
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    Plus one from me, this is the best way to do what you want. More precisely look in /etc/crontab file and you will see, that after the time template and before the command there is "root" written there. This means that "root" runs those commands. Just add your own schedule and instead of "root" use any user. Also, note that if you use per user crontabs (as sugested by Eric D) you may loose the functionality of the system wide crontab (/etc/crontab and /etc/cron.d).
    – Patkos Csaba
    Aug 2, 2010 at 12:25
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    The preferably solution I guess would be to just crontab -u <user> -e to keep everything in one place, which you can do as root. I like to group my cron jobs by function, though, instead of just by user, so this is the preferable solution for me.
    – Sera H
    Sep 5, 2017 at 10:46
49

As root, to edit the cron of user1:

crontab -u user1 -e

You can also start your command with:

su user1 -c foo bar

But often, the scripts themselves reduce their own access when started as root.

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2

I have been looking for this for a couple weeks and this finally worked...

Create your script as user1

ssh user1@ipaddress
nano hourly-event.sh

enter some command

#!/bin/bash
echo "YAY it works" > /home/user1/yay.txt

make it executable

chmod 755 hourly-event.sh

edit the crontab for user1

sudo crontab -u user1 -e

put a line at the bottom pointing to your script(s)

# m h  dom mon dow   command
*   *   *   *   *    bash ./hourly-event.sh

exit - saving changes (it will show a /tmp directory when saving... it's ok)

wait for the turn of the minute

open your newly create yay.txt

nano /home/user1/yay.txt

you should now have a nano window open with "YAY it works" as the first and only line if the bottom of your nano window say New File... well.. i dunno

you can also check your newly crontab entry for user1 at: /var/spool/cron/crontabs/user1

PEACE

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1

Sometimes you may want the user load his environment, especially when using rbenv, nvm, just like this:

0 0 * * * source ~/.bash_profile && cd /opt/app/current && bundle exec ruby ...

(here the command source ~/.bash_profile will load your Ruby or Node environment.)

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