This cheat sheet provides a quick reference for some common
crontab commands and concepts.
cron is a job scheduler that allows you to automate tasks on Unix-like operating systems.
Cron jobs are defined using a syntax that specifies when and how often a job should run:
* * * * * command_to_run
| | | | |
| | | | +--- Day of the week (0 - 7) (Sunday is both 0 and 7)
| | | +----- Month (1 - 12)
| | +------- Day of the month (1 - 31)
| +--------- Hour (0 - 23)
+----------- Minute (0 - 59)
Cron syntax allows for special characters:
*: Wildcard, matches all possible values for a field.
,: Specifies a list of values.
-: Specifies a range of values.
/: Specifies a step value.
Cron jobs run in a minimal environment. You may need to specify the full path to commands and set environment variables.
Edit the current user's crontab:
List the current user's crontab entries:
Remove the current user's crontab:
Schedule a Daily Backup
0 2 * * * /path/to/backup-script.sh
This example schedules a backup script to run daily at 2:00 AM.
Run a Script Every Hour
0 * * * * /path/to/script.sh
This example runs a script every hour at the beginning of the hour.
Schedule Weekly Maintenance
0 3 * * 6 /path/to/maintenance-script.sh
This example schedules a maintenance script to run every Saturday at 3:00 AM.
Schedule a Monthly Report
0 0 1 * * /path/to/report-script.sh
This example schedules a monthly report script to run on the first day of each month at midnight.
This cheat sheet covers some common
crontab commands and concepts for scheduling and automating tasks in Unix-like operating systems.
cron is a versatile tool for automating recurring tasks; refer to the official cron documentation for more in-depth information and advanced usage.