Borg Backup Script

borg_backup.sh

#!/bin/bash

# Exit immediately if a command exits with a non-zero status
set -e

# Variables (Customize these)
BACKUP_REPO="/path/to/backup/repo"    # Borg repository location
BACKUP_SOURCE="/path/to/backup/source"  # Directory to back up
PASSPHRASE="your-borg-passphrase"       # Borg passphrase (avoid exposing in scripts; use environment variables instead)
BACKUP_LOG="/var/log/borg_backup.log"  # Log file location
PRUNE_OPTIONS="--keep-daily=7 --keep-weekly=4 --keep-monthly=6"  # Prune policy

# Export passphrase for Borg
export BORG_PASSPHRASE="$PASSPHRASE"

# Timestamp for backup archive
TIMESTAMP=$(date +"%Y-%m-%d_%H-%M-%S")
ARCHIVE_NAME="backup-$TIMESTAMP"

# Function to log messages
echo_log() {
    echo "[$(date +"%Y-%m-%d %H:%M:%S")] $1" | tee -a "$BACKUP_LOG"
}

# Check if Borg repository exists
if ! borg list "$BACKUP_REPO" &>/dev/null; then
    echo_log "Initializing new Borg repository at $BACKUP_REPO"
    borg init --encryption=repokey "$BACKUP_REPO"
fi

# Create a backup
echo_log "Starting backup: $ARCHIVE_NAME"
borg create --stats --progress \
    "$BACKUP_REPO::$ARCHIVE_NAME" \
    "$BACKUP_SOURCE" \
    2>> "$BACKUP_LOG"
echo_log "Backup completed: $ARCHIVE_NAME"

# Prune old backups
echo_log "Pruning old backups"
borg prune --list "$BACKUP_REPO" $PRUNE_OPTIONS 2>> "$BACKUP_LOG"
echo_log "Prune completed"

# Check repository integrity (optional, but recommended)
echo_log "Checking repository integrity"
borg check "$BACKUP_REPO" 2>> "$BACKUP_LOG"
echo_log "Repository integrity check completed"

# Unset passphrase for security
unset BORG_PASSPHRASE

# Done
echo_log "Backup process completed successfully"