Cron Scheduler Skill

A comprehensive skill for managing cron jobs on both macOS and Linux systems.

Features

List Jobs - View all cron jobs for the current user
Add Job - Create new cron jobs with schedule validation
Remove Job - Delete jobs by line number or pattern
Edit Crontab - Open crontab in your default editor
Next Runs - See when each job will execute next
Backup/Restore - Safely backup and restore crontab configurations
Service Control - Start/stop/status of cron daemon
Templates - Common schedule patterns for quick setup

Requirements

crontab command (pre-installed on macOS/Linux)
bash shell
Optional: cronnext for accurate next-run predictions (Linux)

Installation

# Make the script executable
chmod +x ~/.openclaw/workspace/skills/cron-scheduler/scripts/cron-helper.sh

# Optional: Add to PATH
echo 'export PATH="$HOME/.openclaw/workspace/skills/cron-scheduler/scripts:$PATH"' >> ~/.zshrc
source ~/.zshrc

Usage

List all cron jobs

cron-scheduler list
# or
cron-scheduler l

Add a new cron job

# Daily backup at 2am
cron-scheduler add "0 2 * * *" "~/scripts/backup.sh"

# Every hour
cron-scheduler add "0 * * * *" "~/scripts/hourly-task.sh"

# Every 5 minutes
cron-scheduler add "*/5 * * * *" "~/scripts/monitor.sh"

Remove cron jobs

# By line number (use 'list' first to see line numbers)
cron-scheduler remove 3

# By pattern (matches anywhere in the line)
cron-scheduler removep "backup"

Edit crontab directly

cron-scheduler edit
# or
cron-scheduler e

Show next run times

cron-scheduler next
# or
cron-scheduler n

Backup and restore

# Create backup
cron-scheduler backup

# List available backups
cron-scheduler restore

# Restore specific backup
cron-scheduler restore ~/.cron-backups/crontab_20240315_143022.bak

Manage cron service

# Check status
cron-scheduler service status

# Start cron (may require sudo)
cron-scheduler service start

# Stop cron (may require sudo)
cron-scheduler service stop

View templates

cron-scheduler templates
# or
cron-scheduler t

Cron Schedule Format

┌──────────── minute (0 - 59)
│ ┌────────── hour (0 - 23)
│ │ ┌──────── day of month (1 - 31)
│ │ │ ┌------ month (1 - 12)
│ │ │ │ ┌---- day of week (0 - 6, Sunday=0)
* * * * *

Common Examples

Schedule	Description
`0 0 * * *`	Daily at midnight
`0 2 * * *`	Daily at 2am
`0 * * * *`	Every hour
`/5 * * *`	Every 5 minutes
`0 9 * * 1-5`	Weekdays at 9am
`0 0 * * 0`	Weekly on Sunday
`0 0 1 * *`	Monthly on 1st

Platform Support

macOS: Uses launchctl for service management
Linux: Uses systemctl for service management

Safety Features

Temporary files used for atomic crontab modifications
Backup created before any destructive operations
Confirmation prompt before restore
Schedule validation before adding jobs