Crontab

List (-l), edit (-e) and remove (-r) crontab entries

crontab -l
crontab -e
crontab -r

Edit crontab for a different user

sudo -u <user> crontab -e

Example crontab entry (run php script every 30 minutes)

30 * * * * cd /path/to/script; php -q script.php > /dev/null

Timing format

• min (0-59) / hour (0-23) / day of month (1-31) / month (1-12) / day of week (0-6, 0=Sunday)

• Use asterisk in a specific slot to represent every instance (eg. every hour, day etc)

Crontab Command Tips

• Separate multiple statements for one cron instruction with ;

• Suppress error/output by redirecting result to > /dev/null