Combining Versions: sccs comb

The comb subcommand generates a Bourne shell script that, when run, constructs a new history file in which selected deltas are combined or eliminated. This can be useful when disk space is at a premium.

In combining several deltas, the comb-generated script destroys a portion of the file's version log, including comments.

The -psid option indicates the oldest delta to preserve in the reconstruction. Another option,

-c sid-list

allows you to specify a list of deltas to include. sid-list is a comma-separated list; you can specify a range between two SIDs by separating them with a dash ('-') in the list. -p and -c are mutually exclusive. The -o option attempts to minimize the number of deltas in the reconstruction.

The -s option produces a script that compares the size of the reconstruction with that of the original. The comparison is given as a percentage of the original the reconstruction would occupy, based on the number of blocks in each.

When using comb, it is a good idea to keep a copy of the original history file on hand. While comb is intended to save disk space, it does not always work. In some cases, it is possible that the resulting history file might be larger than the original.

If no options are specified, comb preserves the minimum number of ancestors needed to preserve the changes made so far.