Tracking versions with SCCS

comb

The comb command lets the user reduce the size of an SCCS file. It generates a shell procedure on the standard output, which reconstructs the file by discarding unwanted deltas and combining other specified deltas. (It is not recommended that comb be used as a matter of routine.)

In the absence of any keyletters, comb preserves only leaf deltas and the minimum number of ancestor deltas necessary to preserve the shape of an SCCS tree. The effect of this is to eliminate middle deltas on the trunk and on all branches of the tree. Thus, in ``Extended branching concept'', deltas 1.2, 1.3.2.1, 1.4, and 2.1 would be eliminated.

Some of the keyletters used with this command are:

comb -s: This option generates a shell procedure that produces a report of the percentage space (if any) the user will save. This is often useful as a preliminary check.
comb -p: This option is used to specify the oldest delta the user wants preserved.
comb -c: This option is used to specify a list (see the get(1) page for its syntax) of deltas the user wants preserved. All other deltas will be discarded.

The shell procedure generated by comb is not guaranteed to save space. A reconstructed file may even be larger than the original. Note, too, that the shape of an SCCS file tree may be altered by the reconstruction process.