How to make patch files to contribute to contributed modules

Description

These instructions assume a GNU-Linux, Mac OS X, or other UNIX-y computing environment.

Follow these instructions for using CVS:

http://drupal.org/patch/create

However, if you are making a patch for a contributed module rather than Drupal core, going to the Drupal root directory doesn't make sense.

For a change to a single file (not adding or removing a file), you can just make a copy of the original file, call your new file _original and list the file you change (the one without a rename in this case) second in the diff command.

And create the actual patch from within the module directory:

diff -up token_node_original.inc token_node.inc > token_5_reroll.patch

Update: see recommended patch naming conventions!