git checkout -b freds_fixbug42 git am --keep-cr -s < their-patch-file.diff
- make sure you have a clean local checkout
- no need to check on multiple OSes (unless the ticket is specific to this)
- Please note the -s above, it is important, as it indicates that you are the one accepting this patch.
- The --keep-cr helps when files being patched contain DOS CR/LF line endings. It seems to be harmless when it isn't needed, but leave it off or use --no-keep-cr if you suspect it is causing issues.
Once you have a working copy, you should take note of the following kinds of things: