aecomp script is used to compare two changes, using tkdiff(1) to display
the changes. If you give one change on the command line, the other
change is determined in the usual way. If you give two changes, those
are the two compared. Both changes must be in the being developed
state (its only a script, after all).
Basically, aecomp allows you to specify two project/change pairs (ie the
compared changes dont have to be in the same branch or project). aecomp
attempts to use defaults (for project and change number) where possible.
As a minimum, it needs a single change number as an option. A list
of files which are common between the two changes is constructed and
presented. Double clicking on any of the file names will tkdiff
the two versions (ie the files in each change).
It is useful after you have used aeclone(1), then modified a change
and subsequently are wondering what on earth you did. Files are considered
to be "common" if they have the same name. In the case of a file which
has been moved, its original filename is used (the diff of course takes
place against the new file name).