How to make a patch file
Whats a patch?
A patch is the best and easiest way to submit changes back to an open
source project. It’s a summary of changes you made to file or files
formatted in a way that can easily be used by the excellent program,
named, unsurprisingly, ‘patch’. Now because patch was written by the
inestimable Larry Wall, patches can come in a wide range of shapes,
sizes, and formats, and they will apply with a high degree of “do what
I mean”-ness. However, there are some tips to produce high quality
patches.
Slightly Longer Answer
The diff command’s headers should
have dates and times in Universal Time using traditional
Unix format, so that patch recipients can use the -Z or
–set-utc option. Here is an example command, using
Bourne shell syntax:
TZ=UTC0 diff -Naur gcc-2.7 gcc-2.8
Tips for Generating Usable Patch Files
- Tell your recipients how to apply the patch by telling them which directory to cd to, and which patch options to use.
- State clearly what the patch is suppose to accomplish, and which version it is meant to be applied to.
- Your patch will be easier to apply if you place the original and
patched sources next to each other in the file hierarchy so that the
path depths to the files will be the same. - You can produce patches for entire directories of files, not just a
single file, however try to keep your patches relatively
straightforward, and thematically linked. This makes it easier to
understand when something goes wrong. - I’m sure there are others. Did I miss your favorite?
Code improvements, and bug fixes are great, are wonderful, but patches make it much much easier to use them.
