Cron Jobs Cheat Sheet

Crontab syntax, scheduling patterns, and management commands for automating recurring tasks on Linux systems.

1 PageBeginnerFeb 5, 2026

Crontab Syntax

Five time fields plus the command to run.

bash

# minute hour day-of-month month day-of-week  command# *      *    *            *     *# |      |    |            |     |# |      |    |            |     +-- 0-7 (0 or 7 = Sunday)# |      |    |            +-------- 1-12# |      |    +--------------------- 1-31# |      +-------------------------- 0-23# +--------------------------------- 0-590 2 * * *   /usr/local/bin/backup.sh        # Every day at 2:00 AM*/15 * * * * /usr/local/bin/healthcheck.sh  # Every 15 minutes0 9 * * 1-5 /usr/local/bin/report.sh        # 9 AM on weekdays

Managing Crontabs

View, edit, and remove crontabs.

bash

crontab -e                # Edit current user's crontabcrontab -l                # List current user's crontabcrontab -r                # Remove current user's crontabcrontab -u alice -l       # List another user's crontab (as root)sudo cat /etc/crontab     # System-wide crontab (includes user field)ls /etc/cron.d/           # System job definitions dropped by packages

Special Strings & Notes

Shorthand macros and common gotchas.

@reboot- Runs the command once at system startup
@daily / @midnight- Equivalent to '0 0 * * *'
@hourly- Equivalent to '0 * * * *'
@weekly- Equivalent to '0 0 * * 0'
MAILTO=- Set at the top of a crontab to email job output to an address
PATH=- Cron runs with a minimal environment; set PATH explicitly if scripts rely on it

Pro Tip

Always redirect output explicitly (e.g. >> /var/log/job.log 2>&1) and use absolute paths in cron scripts — cron's minimal environment and lack of a terminal are the #1 cause of 'it works when I run it manually but not from cron' bugs.

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