smudge and clean

the basic idea

git provides filters which you can access via your attributes and config files.

This project sets up simple smudge and clean filters to demonstrate how they work.

context

More info here

how it works

Filters are arbitrary Unix software. They must conform to the standard interface for all Unix software: take input via stdin, write output to stdout, exit with a 0 for success or any number up to 255 for failure, etc. Unfortunately, git seems to suppress filter output whether it happens on stdout or stderr.

However, "arbitrary Unix software" means you can implement these filters in a huge range of ways. You could easily use a Node.js "binary" prepared in the npm way, or a Ruby "binary" prepared in the gem way.

The clean and smudge filters in this directory are simple bash scripts which run simple one-line Ruby commands. They convert tabs into spaces when you check a file out, and convert spaces into tabs when you commit a file. They read from stdin and write to stdout using Ruby's $stdin and $stdout global variables.

The files git.config.sample and git.attributes.sample show lines you should add to your config and attributes files in order to make this work. Those files live at either .git/info/attributes (project-local) or .gitattributes (global), for attributes, and either .git/config (project-local) or .gitconfig (global), for config.

details

Note that,

1. The clean and smudge filters in this directory do not apply to every file. Rather, they will only affect files with names like *.tabs. This behavior is set by the contents of the attributes file: for this example, git.attributes.sample. You can of course change that behavior by editing that file.
2. git needs to know where to find your clean and smudge filters. You tell git where by setting contents of the config file: for this example, git.config.sample. You will need to edit that file (in your local repository) to make the paths in that file match the locations at which you have placed those scripts.