I'd like to diff a bunch of lines across several revisions. Like, I'd like to see a.c, b.c, and c.c from changelist X to changelist Y.

p4 diff2 a.c@X a.c@Y (where X & Y are changelist numbers) seems to work, but only sometimes. Specifically, if a.c is non-existent at X, I don't get a diff. I'd like to be able to get the diff (even though it'll be the whole file with only adds) anyways.

To get the bigger picture: I have several files, across several commits, and I'd like to merge the diffs of these files in these commits, to basically say "this is a diff of what changed in this set of files during this set of changelists"