Linux: Manage scripts via cron job

The Cron daemon is a built-in Linux utility that runs processes on your system at a scheduled time. Cron reads the crontab (cron tables) for predefined commands and scripts.

Cron jobs run as the current user are define in your user’s crontab file. To open it run

$ crontab -e

You may need to select an editor on first usage.

At the bottom, create a new, single line entry in the following manner:

<SCHEDULE_EXPRESSION> [<PATH_TO_COMMAND>]<COMMAND> [<ARGUMENTS>] [OUTPUT]

where the SCHEDULED_EXPRESSION defines how often crontab triggers a command. Use the crontab guru to create such an expression.

If your command is only reachable from a specific directory, also specify the PATH_TO_COMMAND

Finally, define the COMMAND you want crontab to run.

If your command requires further ARGUMENTS, enter them after the command, like you would when running the command manually.

The OUTPUT is also optional, defining if where the executable defers the output, for example into a file

Example:

# Print contents of a directory every 10 minutes and write to output.log
*/5 * * * * /usr/bin/make -f /some/directory/Makefile do_this > output.log