comb(CP) 6 January 1993 comb(CP) Name comb - combine SCCS deltas Syntax comb [ -o ] [ -s ] [ -pSID ] [ -clist ] files comb - Description The comb command generates a shell procedure (see sh(CP)) which, when run, will reconstruct the given SCCS files. The reconstructed files will, hopefully, be smaller than the original files. The arguments may be specified in any order, but all arguments apply to all named SCCS files. If a directory is named, comb behaves as though each file in the directory were specified as a named file, except that non-SCCS files and unreadable files are silently ignored. If a name of - is given, the standard input is read; each line of the input is taken to be the name of an SCCS file to be processed. The generated shell procedure is written to standard output. The arguments are as follows. Each is explained as though only one named file is to be processed, but the effects of any argument apply independently to each named file. -o For each get -e generated, this argument causes the reconstructed file to be accessed at the release of the delta to be created, other- wise the reconstructed file would be accessed at the most recent ancestor. Use of the -o may decrease the size of the reconstructed SCCS file. It may also alter the shape of the delta tree of the ori- ginal file. -s This argument causes comb to generate a shell procedure that, when run, produces a report giving the following for each file: the file name, the percentage change in file size after combining, the total file size (in blocks) after combining, and the original file size (also in blocks). The format of the report is as follows: filename [+-]percentage_change newsize/oldsize A sample command line to use this option would look like this: comb -s s.filename | sh > report where report is the name of the file that receives the report infor- mation. It is recommended that before any SCCS files are actually combined, you should use this option to determine exactly how much space can be saved through the combining process. -pSID The SID (SCCS identification string) of the oldest delta to be preserved. All older deltas are discarded in the reconstructed file. For example, if you give the command: comb -p 1.5 s.filename All deltas from 1.5 to the most recent delta will be preserved. All deltas prior to 1.5 will be removed. -clist This command causes the existing deltas in the subject file to be combined. It then overwrites the subject file with the new com- bined delta. For example, if you give the following command: comb -c1.4 s.workfile | sh all previous deltas to s.workfile will be combined, and the new combined delta will be number 1.4. If no arguments are specified, comb will preserve only leaf deltas and the minimal number of ancestors needed to preserve the tree. Files s.COMB The name of the reconstructed SCCS file. comb????? Temporary file. Notes The comb command may rearrange the shape of the tree of deltas. It may not save any space; in fact, it is possible for the reconstructed file to actually be larger than the original. See also admin(CP), delta(CP), get(CP), prs(CP), sccsfile(FP), sh(C)