comb Command (SCCS)

Purpose

Combines SCCS deltas.

Syntax

comb [ -o ] [ -s ] [ -c List | -p SID ] File

Description

The comb command writes to standard output a shell procedure that can combine specified SCCS deltas (SIDs) or all deltas into one delta. You can reduce the size of your Source Code Control System (SCCS) file by running the resulting procedure on the file. To see how much the file will be reduced, run the comb program with the -s flag. If you specify a directory for the File value, the comb command performs the requested actions on all SCCS files (that is, those having an s. prefix). If you specify a - (minus) for the File value, the comb command reads standard input and interprets each line as the name of an SCCS file. The comb command continues to take input until it reads an end-of-file character.

If you do not specify any flags, the comb command preserves only leaf deltas and the minimal number of ancestors needed to preserve the tree.

Note: The comb command may rearrange the shape of the tree deltas. It may not save any space. In fact, it is possible for the reconstructed file to actually be larger than the original.

Flags

Note: Each flag or group of flags applies independently to each named file.

Item	Description
-c List	Specifies a list of deltas (SIDs) that the shell procedure will preserve (see the get command -i List flag). The procedure combines all other deltas.
-o	Accesses the reconstructed file at the release of the delta to be created for each get command -e flag generated; otherwise, accesses the reconstructed file at the most recent ancestor. Using the -o flag may decrease the size of the reconstructed SCCS file. It may also alter the shape of the delta tree of the original file.
-p SID	Specifies the SID of the oldest delta for the resulting procedure to preserve. All older deltas are combined in the reconstructed file.
-s	Causes the comb command to generate a shell procedure that produces a report for each file listing: the file name, size (in blocks) after combining, original size (also in blocks), and percentage change computed by the formula: `100 * (original - combined) / original` You should run the comb program using this flag and then run its procedure before combining SCCS files in order to judge how much space will actually be saved by the combining process.

Examples

To generate a report on how much space will be saved by combining all deltas older than SID 1.4 for sccs file s.test.c, enter:
```
comb -p1.4 -s s.test.c
```
Run the report by piping the output of the above command to the sh command.
To actually perform the combination, enter:
```
comb -p1.4 s.test.c
```

Files

Item	Description
s.COMB	The name of the reconstructed SCCS file.
comb*	Temporary files.