Scheduling Tasks with Cron

Using Cron to schedule a backup of important files

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Category : network   server   docker   cron


Using Cron to schedule a backup of important files

To have your script run once every day, you can use cron, which is a Linux utility for scheduling tasks. Here’s how you can set it up:

Steps to Schedule the Script with Cron:

  1. Place your script in a directory:
    Ensure that the create_backup.sh script is saved somewhere on your server, for example, in /srv/scripts/create_backup.sh.

  2. Make the script executable:
    Make sure the script has the appropriate executable permissions: 
    chmod +x /srv/scripts/create_backup.sh
  3. Edit the root user’s crontab:
    Since the script needs to run as root, you will need to add it to the root user’s crontab. You can do this by running: 
    sudo crontab -e

  4. Add a cron job to run the script daily:
    Add the following line to the root’s crontab file to schedule the script to run every day at, for example, 2:00 AM:

    0 2 * * * /srv/scripts/create_backup.sh

    Explanation of the cron syntax:

    • 0 2 * * * means “at 2:00 AM every day.”
    • /srv/scripts/create_backup.sh is the full path to the script.

    If you want it to run at a different time, you can modify the time accordingly:

    • First value: minute (0-59)
    • Second value: hour (0-23)
    • Third value: day of the month (1-31)
    • Fourth value: month (1-12)
    • Fifth value: day of the week (0-7, where both 0 and 7 are Sunday)
  5. Save and Exit:
    After adding the line, save and exit the crontab editor (in most editors, Ctrl + O to save and Ctrl + X to exit).

Verifying the Cron Job:

  • To verify that the cron job has been added, you can list the cron jobs with: 
    sudo crontab -l

Now, the create_backup.sh script will run automatically every day at 2:00 AM (or your chosen time).

Log Output:

If you want to log the script’s output to a file for troubleshooting or review, you can modify the cron job to include a redirection to a log file:

0 2 * * * /srv/scripts/create_backup.sh >> /var/log/backup_script-config.log 2>&1

This will append both standard output and error messages to /var/log/backup_script.log.

Backup Script

My backup script create a package with the files and directories listed and save it in a directory that is duplicated

#!/bin/bash

# ┌────────────────────────────────────────────────────────────────────────────────┐
# │                                                                                │
# │   create_backup.sh                                                             │
# │   a script that will create a package with the files and directories below     │
# │   needs to be run as root. It will create a package to restore the files later │
# ┼────────────────────────────────────────────────────────────────────────────────┼
# │   Guillaume Plante  <guillaumeplante.qc@gmail.com>                             │
# └────────────────────────────────────────────────────────────────────────────────┘

# Colors for output
UL='\033[4;93m'
IL='\033[3;91m'
BL='\033[6;94m'
CYAN='\033[0;36m'
YELLOW='\033[0;33m'
RED='\033[0;31m'
NC='\033[0m' # No Color

LogCategory=backup

# handy logging and error handling functions
pecho() { printf %s\\n "$*"; }

log() { pecho "$@"; }

# Verbose output function
log_info() {
    echo -e "${CYAN}[INFO] $1${NC}"
    logger --tag $LogCategory -p user.info "[INFO] $1"
}

log_il() {
    echo -e "${IL}$1${NC}"
    logger --tag $LogCategory -p user.info "$1"
}


log_warning() {
    echo -e "${YELLOW}[WARNING] $1${NC}"
    logger --tag $LogCategory -p user.warning "[WARNING] $1"
}
log_error() {
    echo -e "${RED}[ERROR] $1${NC}"
    logger --tag $LogCategory -p user.error "[ERROR] $1"
}
debug() { : log_info "INFO: $@" >&2; }
error() { log_info "ERROR: $@" >&2; }
fatal() { log_error "$@"; exit 1; }
try() { "$@" || fatal "'$@' failed"; }
usage_fatal() { usage >&2; pecho "" >&2; fatal "$@"; }


log_il "\ncreate_backup.sh - creating a backup of my scripts\n"


# Ensure the script is run as root
if [ "$EUID" -ne 0 ]; then
    log_error "Please run as root"
    exit 1
fi

# Directory to store backups
backup_dir="/srv/backup/scripts-config"

# Create backup directory if it doesn't exist
if [ ! -d "$backup_dir" ]; then
    mkdir -p "$backup_dir"
fi

# Set the output filename for the backup tarball
backup_file="$backup_dir/backup_scripts-config_$(date +%Y%m%d).tar.gz"

# List of files and directories to include in the package
files_to_backup=(
    "/root/.ssh"
    "/etc/samba/smb.conf"
    "/etc/initramfs-tools/initramfs.conf"
    "/etc/initramfs-tools/root/.ssh"
    "/home/gp/.ssh"
    "/home/gp/scripts"
    "/srv/secrets"
    "/srv/scripts"
    "/srv/vpn/config"
    "/srv/vpn/scripts"
    "/home/storage/Configs/QBittorrentVPN/openvpn"
    "/home/storage/Configs/QBittorrentVPN/qBittorrent/config"
    "/etc/dropbear"
)

# Excluded directories
excluded_dirs=(
    "--exclude=/srv/vpn/config/vpn-configs-contrib"
    "--exclude=/srv/vpn/config/transmission-home"
)

# Create the tarball, with verbose output (-v), preserving file permissions (-p), and excluding specified directories
log_info "Creating backup package..."
tar -cpvzf $backup_file "${excluded_dirs[@]}" --absolute-names "${files_to_backup[@]}"

# Check if the tarball was created successfully
if [ $? -eq 0 ]; then
    log_info "Backup successfully created at: $backup_file"
else
    log_error "An error occurred while creating the backup."
    exit 1
fi

# Step to delete backups older than 10 days (log rotation)
log_info "Performing log rotation, deleting backups older than 10 days..."
find $backup_dir -type f -name "backup_*.tar.gz" -mtime +10 -exec rm -f {} \;

log_info "Backup creation and log rotation complete."

About Guillaume Plante
Guillaume Plante

A developper with a passion for technology, music, astronomy and art. Coding range: hardware/drivers, security, ai,. c/c++, powershell

Email : guillaumeplante.qc@gmail.com

Website : https://arsscriptum.ddns.net

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