Name

crontab

Synopsis

    crontab [file]
    crontab options [user]

View, install, or uninstall your current crontab file. On Mac OS X and GNU/Linux, a privileged user can run crontab for another user by supplying -u user. On Solaris, supply user following one of -e, -l, or -r.

A crontab file is a list of commands, one per line, that executes automatically at a given time. Numbers are supplied before each command to specify the execution time. The numbers appear in five fields, as follows:

Minute            0-59
    Hour               0-23
    Day of month          1-31
    Month            1-12
    Day of week           0-6, with 0 = Sunday

Use a comma between multiple values, a hyphen to indicate a range, and an asterisk to indicate all possible values. For example, assuming the crontab entries below:

    59 3 * * 5          find / -print | backup_program
    0 0 1,15 * *        echo "Timesheets due" | mailuser

The first command backs up the system files every Friday at 3:59 a.m., and the second command mails a reminder on the 1st and 15th of each month.

Common Options

-e

Edit the user’s current crontab file (or create one).

-l

List the user’s file in the crontab directory.

-r

Delete the user’s file in the crontab directory.

GNU/Linux and Mac OS X Option

-u user

Indicate which user’s crontab file will be acted upon.

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