ClearCase: how to generate a patch (unified diff) file from an activity?

Question

Is it possible to generate an patch file from the changeset of a UCM Activity in ClearCase?

I can generate the list of changes this way: cleartool lsactivity -l activity:my_activity_name

Answer 1

The main approach is list all the files within an activity, and use cleartool diff -pred -diff_format in order to generate a diff.

With the -diff_format option, you would get headers and differences in the same style as the UNIX and Linux diff utility.

But that would require some scripting, as I mentioned in "Change set predecessor using cleartool".

Answer 2

I didn't have much luck with cleartool diff -pred -diff_format. It worked but left a bit to be desired so I fashioned this instead:

diff --unified <file>@@/main/`cleartool pwv -short`/0 <file> >> patch

This allows you to stack multiple files together and apply them all at once. You can use the resulting file with either patch or git apply