How to Run 7-Zip Commands in Linux Cron Jobs

This guide explains how to automate file compression and backups by running 7-Zip commands inside Linux cron jobs. You will learn how to install 7-Zip, write a dependable shell script using absolute file paths and dynamic timestamps, configure the proper execution permissions, and schedule the automated task using the crontab editor.

Step 1: Install 7-Zip on Linux

Ensure the 7-Zip binary is installed on your Linux distribution.

On Debian or Ubuntu:

sudo apt update
sudo apt install 7zip

(On older releases, install p7zip-full instead.)

On RHEL, CentOS, or Fedora:

sudo dnf install epel-release -y
sudo dnf install p7zip p7zip-plugins -y

Verify the installation and locate the absolute binary path:

which 7z

Common paths are /usr/bin/7z or /bin/7z. Note this path, as cron requires absolute paths to function reliably.

Step 2: Create a Backup Shell Script

While you can run 7-Zip directly inside crontab, wrapping the command in a shell script allows you to handle timestamps, multi-directory targets, and error logging much more cleanly.

Create a script file:

nano /usr/local/bin/cron_backup.sh

Paste the following script, replacing directories with your actual paths:

#!/bin/bash

# Configuration
BIN_7Z="/usr/bin/7z"
SRC_DIR="/var/www/html"
DEST_DIR="/backup"
DATE=$(date +"%Y-%m-%d_%H%M%S")
ARCHIVE_NAME="$DEST_DIR/backup_$DATE.7z"

# Ensure the backup directory exists
mkdir -p "$DEST_DIR"

# Execute 7-Zip compression
# -mx=9 sets ultra compression (optional, default is -mx=5)
# -p adds a password if needed (e.g., -p"SecretPassword")
$BIN_7Z a -mx=9 "$ARCHIVE_NAME" "$SRC_DIR" > /dev/null 2>&1

Step 3: Set Execution Permissions

Make the script executable by root or the user running the cron job:

chmod +x /usr/local/bin/cron_backup.sh

Test the script manually to confirm it creates the archive without errors:

/usr/local/bin/cron_backup.sh

Verify that the .7z file was created in your destination directory before scheduling it.

Step 4: Schedule the Script in Cron

Open the cron table editor for your user or root:

crontab -e

Add an entry specifying the time interval and the script path.

Example Schedules:

  • Run daily at 2:00 AM:

    0 2 * * * /usr/local/bin/cron_backup.sh >> /var/log/7z_backup.log 2>&1

  • Run every Sunday at midnight:

    0 0 * * 0 /usr/local/bin/cron_backup.sh >> /var/log/7z_backup.log 2>&1

  • Run every 6 hours:

    0 */6 * * * /usr/local/bin/cron_backup.sh >> /var/log/7z_backup.log 2>&1

The >> /var/log/7z_backup.log 2>&1 directive appends all standard output and error messages to a log file, which helps with troubleshooting if an archive operation fails. Save and exit the editor; cron will immediately load the new schedule.