Cron expression builder

Standard five-field cron (minute hour day-of-month month day-of-week). Validate against your scheduler (systemd, k8s, cloud) before use.

Minute

Hour

Day of month

Month

Day of week

Expression

0 9 * * *

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Terminal Equivalent

Manage user crontabs and validate schedules with the same tools your Linux server uses.

bash

# View current crontab
crontab -l

# Edit crontab
crontab -e

# Run a command every day at 9am
# 0 9 * * * /path/to/command

# Every Monday at midnight
# 0 0 * * MON /path/to/command

# Every 15 minutes
# */15 * * * * /path/to/command

# Test when a cron will next run (using GNU date)
# Install: sudo apt install ncal
# Check next 5 occurrences:
echo "Next 5 runs of '0 9 * * *':"
for i in 1 2 3 4 5; do
  date -d "$(date -d 'tomorrow' +%Y-%m-%d) + $((i-1)) days" \
  "+%Y-%m-%d 09:00:00"
done

# View cron logs
grep CRON /var/log/syslog | tail -20

How It Works

A cron expression has 5 fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-7, where both 0 and 7 = Sunday). Asterisk (*) means 'every'. Slash (/) means 'every N' — */15 means every 15 units. Comma separates values: MON,WED,FRI means those three days. Systems like AWS EventBridge and Kubernetes use 6-field cron with seconds. Quartz scheduler uses 7 fields including year.