cron-ological

• I can't ever remember the crontab format, so I always put this in the top of mine (copied from the man page, which is “man 5 crontab”)

  • # minute 0-59 # hour 0-23 # day of month 1-31 # month 1-12 (or names, see below) # day of week 0-7 (0 or 7 is Sun, or use names)

• Example lines

  • 0 */6 * * * ~/public_html/pisg/run-pisg >/dev/null 2>&1 30 */2 * * * ~/public_html/pisg/topic.sh 0 0 * * * cat /dev/null > ~/procmail.log 2 2 * * * ~/bin/delspam

• crontab -e, crontab -l

• Keep in mind /etc/cron* directorys, plus root's crontab

• If your cron generates output, it will be mailed to you. So check those mailboxes!

• Put commands to run at boot-time in /etc/rc.d/rc.local

Notes: