git-absorb

This tool merges multiple local git repositories into a single monolithic repository while still maintaining the history from each combined repository. Each merged repository is located in a subdirectory with the name of the source repository.

The usefullness of this tool is mainly in its ability to automate the grouping of a collection of related repositories. For example, at my university many of my programming classes have separate repositories for each assignment. Using this tool I can merge all those repositories together and back it up to my own GitHub account, etc. Preserving the history from each repository is helpful for me so I can go back and understand my thought process of solving some specific problem.

Caveats

I don't really recommend using this to merge particularly complex repos. I haven't tested this tool on repositories with more than a couple of branches each, so YMMV with more complex repositories (i.e. avoid the --clean flag).

Additionally, this tool doesn't check for hash collisions between two separate repositories. I expect that is extremely unlikely to happen, and would likely require effort in order to accomplish.

Installation

Homebrew is the recommended installationation method. Just run the following commands to get started.

$ brew tap mrflynn/cider
$ brew install mrflynn/cider/git-absorb

Alternatively, you can install the tool manually by cloning this repository and adding bin/ and man/ to your PATH and MANPATH variables, respectively.

Usage

$ git absorb --help
Usage: git absorb [FOLDER ...] [OPTIONS]
  Combines multiple repositories into one while preserving history.

  The folder argument is required for the script to run.

  Options:
  -c  --clean   Remove local copies of repositories merged into
                the new repository when script has finished.
  -h  --help    Display this menu and exit immediately.

Goals

These were my goals when writing this program:

1. Attain a better understanding of how to write bash scripts. Functions, globbing, data manipulation, arrays, error checking and handling, and script flags.
2. Develop a better understanding of git--more specifically with merges. How to combine multiple histories seamlessly was important.
3. Familiarize myself with code linting tools, particularly those that exist for shell script. I am using ShellCheck as my linter for this project.