Diffs is a perl script to generate unix diffs in the format that will be accepted as patched by SPW.
It is available [http://purl.net/net/spw/spw.pl?action=showfile&path=\/spw\/diffs here].
The syntax is diffs orig_file_copy modified_file > patch_file, for example,
:diffs spw_main.pl.old spw_main.pl > my_patch
All it does is run the unix diff -C2 command and then alter the paths in the diff so that they will work with the command patch -d/ -p0 which SPW will use. If you want to, you can just run diff -C2 instead of diffs and then edit the paths yourself; the final paths should be absolute paths in SPW's file system, i.e. something like /spw/bin/spw_main.pl).