Periodic-backup-bash-script

A simple Bash backup helper that creates tarball and directory backups and synchronizes them to a remote host using rsync + SSH. The script also installs cron jobs (under /etc/cron.d) to run tarball and directory backups on a schedule.

Intended host: Linux systems with Bash and rsync installed (run as root or with sufficient privileges to read listed paths and write cron files).

Working Snapshots

Backup files at Remote server

Log File output

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Quick Summary:

• Tarball mode: run the script with the tarball argument to create a compressed tarball of configured paths and push it to the remote rsync location.
• Directories mode: run the script with the directories argument to sync the specified paths (preserving structure) to the remote host.
• Running the script without tarball/directories will still ensure the cron jobs are present (it writes files under /etc/cron.d).

Requirements

• Bash
• rsync installed and available on PATH
• SSH pubic key configured on the remote host (the script creates a temporary SSH private key file by default)
• Permissions to write to /etc/cron.d (to install cron jobs)

Configuration (in the script)

Open the script and update these variables to suit your environment:

• bpaths — array of files/directories to include in backups. Example entries are already present; remove or add entries as needed.
• rsync_path — remote rsync path in the form <user>@<host>:<remote_backup_path> (replace placeholders).
• cron_schedule_tar — cron schedule for tarball backups (default: 0 1 * * 6 = 01:00 on Saturday).
• cron_schedule_dir — cron schedule for directory syncs (default: 0 2 * * * = 02:00 every day).
• base_path — base working directory where temporary tarball, log, and SSH key are placed (defaults to $HOME).
• ssh_key — path used by the script to write a temporary SSH private key. By default it is $base_path/sshkey.

SSH key placement

• The corresponding public key (the .pub file contents) must be appended to the remote user's ~/.ssh/authorized_keys on the remote server so passwordless SSH from the backup host is allowed. Example on the remote server:

# on remote host, as the backup-receiving user
mkdir -p ~/.ssh && chmod 700 ~/.ssh
echo 'ssh-rsa AAAA... your-public-key ... user@host' >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

Usage

From a shell on the machine hosting the files to backup:

# Create a tarball of the configured paths and rsync it to the remote host
sudo bash /path/to/backup_script.sh tarball

# Sync directories (preserve structure) to the remote host
sudo bash /path/to/backup_script.sh directories

# Run without args to ensure cron jobs are installed
sudo bash /path/to/backup_script.sh

Notes:

• The script checks each bpaths entry and only includes existing files/dirs.
• On tarball the script creates a gzipped tarball named like <hostname>_dYYYYMMDD_tHHMMSS_bkp.tar.gz under base_path.
• rsync calls use an SSH key configured at ssh_key and will transfer the created tarball and logs to the remote rsync_path/$(hostname)/.

Cron Installation

The script will create or update these files under /etc/cron.d:

• /etc/cron.d/backup_script_tarball — contains the cron entry for tarball backups.
• /etc/cron.d/backup_script_directories — contains the cron entry for directory syncs.

Each cron line includes the schedule, the user (script uses $USER), the script path, and the argument (tarball or directories). If you prefer to manage cron yourself, you can comment out that section in the script and create your own cron entries.

Example cron line written to /etc/cron.d/backup_script_tarball (fields: schedule user command arg):

0 1 * * 6 root /path/to/backup_script.sh tarball

Logging

• The script writes stdout/stderr to logfile (default: $HOME/$(hostname)_backup.log).
• After run it attempts to rsync the log file(s) to the remote host as well.

Troubleshooting

• "Please install rsync": install rsync (e.g., apt install rsync or yum install rsync).
• Paths not found: verify each entry in bpaths exists and has readable permissions.
• Permission denied writing to /etc/cron.d: run as root or use proper privilege escalation.
• SSH/rsync failures: verify rsync_path, network connectivity, SSH keys, and remote directory permissions.
• SELinux/AppArmor may prevent writes or execution — check audit.log or disable enforcement for testing.

Where files are written/what the script modifies

• Temporary tarballs/logs/sshkey: default under $HOME (or base_path if changed).
• Cron files: /etc/cron.d/backup_script_tarball and /etc/cron.d/backup_script_directories.

Remote cleanup (recommended)

To avoid backup files accumulating on the remote host you can schedule a cleanup job on the remote server that removes older backups. Example (run as the remote backup-receiving account):

/usr/bin/find /var/images/ipse/ -name "*_bkp.tar.gz" -type f -mtime +30 -exec rm -vf {} \;

Notes:

• Use -mtime +N to remove files older than N days.

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