Many sysadmins encounter contradictory instructions when opening their cron files. The default /var/spool/cron/crontabs/root file typically contains these conflicting lines:

# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (several lines later...)
# Edit this file to introduce tasks to be run by cron.

While the crontab -e command is the recommended approach, manually editing cron files is technically possible if you:

• Maintain proper file permissions (600 for user crontabs)
• Use atomic writes to prevent corruption
• Understand the cron syntax thoroughly

Consider these scenarios where direct editing might be preferable:

# Bulk editing multiple cron jobs
vim /var/spool/cron/crontabs/username

# Programmatic modification (use with caution!)
sed -i '/oldjob/d' /var/spool/cron/crontabs/username
echo "0 3 * * * /path/to/newjob.sh" >> /var/spool/cron/crontabs/username

If you choose manual editing, always:

1. Backup the original file first
2. Verify syntax with crontab -l after editing
3. Check system logs for cron errors

For most users, crontab -e remains the safer choice because it:

• Validates syntax before saving
• Handles file locking properly
• Maintains correct permissions automatically

Advanced users who need direct file access should implement these safety checks:

#!/bin/bash
# Safe edit wrapper for cron files
CRON_FILE="/var/spool/cron/crontabs/$USER"
BACKUP="/tmp/cron_backup_$(date +%s)"

cp "$CRON_FILE" "$BACKUP"
vim "$CRON_FILE" || { echo "Edit failed, restoring backup"; cp "$BACKUP" "$CRON_FILE"; exit 1; }

if ! crontab -l >/dev/null 2>&1; then
  echo "Invalid syntax detected, restoring backup"
  cp "$BACKUP" "$CRON_FILE"
  exit 1
fi

When working with cron jobs, administrators often face the question: should we use crontab -e or manually edit files like /var/spool/cron/crontabs/root? The conflicting comments in default cron files don't help:

# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (minutes) (hours) (day of month) (month) (day of week) (command)
# Edit this file to introduce tasks to be run by cron.

Direct file editing can cause several issues:

• Potential file corruption if the editor doesn't handle file locking properly
• Syntax errors that might not be validated
• Permission problems if the file attributes change
• No automatic backup like crontab -e provides

There are legitimate cases for direct editing:

# Bulk updates - much faster than multiple crontab -e commands
# Example: mass update of paths in existing cron jobs
sed -i 's|/old/path|/new/path|g' /var/spool/cron/crontabs/username

# Scripted deployments where crontab -e isn't practical
cat < /var/spool/cron/crontabs/deployuser
# Maintenance jobs
0 3 * * * /usr/bin/backup.sh
EOF

If you must edit directly:

1. Always create a backup first: cp /var/spool/cron/crontabs/user /backup/user.cron.$(date +%F)
2. Use crontab -l to verify after editing
3. Check file permissions remain correct (usually 600)
4. Validate syntax with crontab -u user -l

Consider these safer methods:

# For system-wide cron jobs (preferred on many distros)
sudo nano /etc/crontab

# Using configuration management tools
# Ansible example:
- name: Ensure cron job exists
  cron:
    name: "daily backup"
    hour: 2
    job: "/opt/backup.sh"