Script to backup GitHub repo(s) to Backblaze B2.

This is the process:

• Download the specified repo to a temporary directory.
• Compress the repo using tar/gzip
• Upload the compressed archive.
• Delete the archive and repo from the temp dir.
• Repeat above steps for any additional specified repos.
• Delete the temp dir itself (if empty).

I wanted to apply safer shell practices to this gist which was featured in this blog entry by Backblaze. Work started as a fork of the gist here but I wanted to support backing up multiple repositories at a time. So I decided to make a full project so I could use features from the BASH3 Boilerplate.

• All variables can be passed as arguments.
• All variables are quoted for safety.
• Exit on any error, not just the specified tests.
• Clone the GitHub repo(s) using either HTTPS or SSH.
• Support backing up multiple repos.
• Authorize the B2 command line tool instead of relying on the user doing so manually.
• Recognize the B2 command line tool from the Arch Linux user repository.
  • (It's named backblaze-b2 instead of b2 see PKGBUILD for details)
• Removed optional file encryption section from source gist.
  • It wouldn't work as expected as it would encrypt the repo but then upload the non-encrypted copy instead.
  • If encryption was going to be used, I would not recommend using a symmetric cipher.

Nilay Patel, for git-backup-to-Backblaze-B2.sh which this script is based on. https://gist.github.com/nilayp/a2719ca5695c1d5a56c556e89207577d