Borgbackup is a deduplicating archiver with compression and encryption. It allows you to store encrypted backups of your data in a space-efficient way. The purpose of this document is to enable the reader to improve their borgbackup process on their macOS machine, using the custom script I have created. If you already have Brew and BorgBackup installed, you can skip ahead to the script.
To install borgbackup on macOS, you first need Homebrew, which is a macOS packet manager.
To begin with, run this:
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"Once brew has been installed, use this to install borgbackup:
brew install borgbackupAt its most basic level, borg works with repositories, or repos, which are used to store your archives. To create a repo, which uses lz4 compression by default, run this command:
borg init --encryption=repokey /path/to/repoOnce a repo has been created, an archive can be added. In the example below, the archive name will contain the current date and time.
borg create --stats --progress ~/repo::'local-{now:%Y-%m-%d-%H%M%S}'To display all archives present in a repo, run:
borg list ~/repoTo obtain more information about the repo, run:
borg list ~/repoTo test your backup, or to recover a previous version of a file, or directory, run:
borg extract ~/repo::archive_nameIf you would like to extract a specific directory from the archive, run:
borg extract ~/repo::archive_name /path/to/extractOn macOS, you have the option to add your repo password to the keychain, via the Terminal. This can be retrieved later on, in order to run the script without typing the password each time.
security add-generic-password -a borg -s BorgBackup -w 'your_password_here'The script below is an example of how borg can be automated with Bash, in order for the backups to occur seamlessly in the background.
#!/bin/bash
echo -e "\n[$(date +"%T")] Local Borg Backup Initialising.\n"
echo "Backing up Brewfile..."
rm -f ~/.config/brew/Brewfile && brew bundle dump --file=~/.config/brew/Brewfile
echo -e "Brewfile has been backed up.\n"
paths=(
"/path"
"/more/paths"
)
BORG_PASSPHRASE=$(security find-generic-password -a borg -s BorgBackup -w) borg create --stats --progress ~/borg/borg.local::'local-{now:%Y-%m-%d-%H%M%S}' "${paths[@]}"
rsync -av --delete ~/borg/borg.local "/Volumes/borg" ; rsync -av --delete ~/borg/borg.local "/Volumes/borg.ssd"
echo -e "\n[$(date +"%T")] Local Borg Backup Complete. \n\n"Below you will find the same script, explained step by step.
echo -e "\n[$(date +"%T")] Local Borg Backup Initialising.\n"This prints an initial message, outputting the current time at the start.
When creating a backup, some users prefer to save their Brewfile as well. This file contains a list of all of the applications installed through brew.
The code below removes the existing Brewfile silently, and brew bundle dump creates an up-to-date version of it.
rm -f ~/.config/brew/Brewfile && brew bundle dump --file=~/.config/brew/BrewfileIn the event that re-installing all of your brew applications is necessary, such as when starting on a new machine, run this to restore it:
brew bundle --file=~/path/to/BrewfileThe next section of the script creates an array of paths. When creating your backup, you can decide which files and directories are to be included. An array is a human-readable way to include every path.
paths=(
"/path"
"/more/paths"
)If you wish to add visual separation between groups of paths, you may leave empty lines.
The next snippet of code can be broken down into two. This first line retrieves the repository password from the macOS keychain.
BORG_PASSPHRASE=$(security find-generic-password -a borg -s BorgBackup -w)The second snippet creates an archive within a repo called borg.local. The "${paths[@]}" section specifies that the entirety of the array must be used.
borg create --stats --progress ~/borg/borg.local::'local-{now:%Y-%m-%d-%H%M%S}' "${paths[@]}"If you wish, you can use rsync in order to disseminate copies of your repos to various destinations. If you do not have rsync installed, you may do so by running:
brew install rsyncOnce installed, you can modify the command below as you wish, to make various copies. The example provided takes the borg.local repo, and copies it to an SD card and an external SSD.
rsync -av --delete ~/borg/borg.local "/Volumes/borg" ; rsync -av --delete ~/borg/borg.local "/Volumes/borg.ssd"In order to provide more redundancy, you may also make cloud backups of your repositories. This can either be done through rsync, or any other third-party app, depending on which cloud backup provider you choose.
Once the backup script has been created, you may use a variation of the code below, in order to run it periodically.
#!/bin/bash
while true; do
bash "/path/to/backup.sh"
echo -e "The next backup will run at [$(date -v +4H +"%T")]\n"
sleep 14400
doneBelow is a step-by-step explanation of the code.
The while true loop just runs forever, until you cancel the script.
This runs the main script, which is what creates the backups.
bash "/path/to/backup.sh"This prints when the next backup will occur. In this particular example, it states that the next backup will occur 4 hours from the current time.
echo -e "The next backup will run at [$(date -v +4H +"%T")]\n"In order for the next backup to be delayed accordingly, sleep must be used. The example below waits for 14400 seconds, which is 240 minutes, or 4 hours. Once the time has elapsed, the loop is initiated again.
sleep 14400Sometimes permissions need to be given to the scripts, in order to work. If that is the case, chmod +x script.sh should solve the issue.