Linux Basic — crontab -e & Shortcuts
crontab -e & Shortcuts
crontab -e opens your user crontab in $EDITOR. Changes take effect immediately when saved.
Commands
| Command | Effect |
|---|---|
crontab -e |
edit your crontab |
crontab -l |
list your crontab |
crontab -r |
remove your crontab (all entries!) |
crontab -u alice -e |
edit alice’s crontab (root only) |
Special Shortcuts
Instead of five fields, use a shortcut:
| Shortcut | Equivalent | Runs |
|---|---|---|
@reboot |
— | once at startup |
@yearly / @annually |
0 0 1 1 * |
Jan 1 at midnight |
@monthly |
0 0 1 * * |
1st of month at midnight |
@weekly |
0 0 * * 0 |
Sundays at midnight |
@daily / @midnight |
0 0 * * * |
every day at midnight |
@hourly |
0 * * * * |
top of every hour |
@daily /opt/backup.sh
@reboot /opt/startup-check.sh
@hourly /opt/health-check.sh
Use shortcuts for clarity when the schedule matches exactly.
Editing Best Practices
- Comment your entries — future-you will thank you
- Use absolute paths for scripts and commands
- Test the command manually before adding to cron
- Check syntax — a malformed line is silently ignored
# daily backup at 2 AM
0 2 * * * /opt/scripts/backup.sh
# check disk space every 15 minutes
*/15 * * * * /usr/local/bin/check-disk.sh
System vs User Crontabs
| Location | Edits via | Use |
|---|---|---|
/var/spool/cron/crontabs/username |
crontab -e |
user jobs |
/etc/crontab |
direct edit (root) | system jobs |
/etc/cron.d/ |
drop files here | package-managed jobs |
System crontabs (/etc/crontab) have an extra user field between time and command:
# minute hour day month weekday user command
0 2 * * * root /opt/backup.sh
Next → cron Environment
