comb.1 (2010 09)

c
comb(1) comb(1)
NAME
comb - combine SCCS deltas
SYNOPSIS
comb [-p SID ][-clist ][
-o][-s] file ...
DESCRIPTION
The
comb command generates a shell procedure (see sh(1)) which, when run, reconstructs the given
SCCS
files. The reconstructed files are usually smaller than the original files. Arguments can be specified in
any order, but all options 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 (last component of the
path name does not begin with
s.) and unreadable files are silently ignored. If a name of
- is given, the
standard input is read; each line of the standard input is taken to be the name of an
SCCS file to be pro-
cessed; non-
SCCS files and unreadable files are silently ignored. The generated shell procedure is written
on the standard output.
Options
comb recognizes the following options. Each is explained as if only one named file is to be processed, but
the effects of any option apply independently to each named file.
-pSID The SCCS IDentification string (SID) of the oldest delta to be preserved. All older
deltas are discarded in the reconstructed file.
-clist A list of deltas to be preserved (see get(1) for the syntax of a list ). All other deltas
are discarded.
-o For each get -e generated, this option causes the reconstructed file to be accessed
at the release of the delta to be created, otherwise the reconstructed file would be
accessed at the most recent ancestor. Use of the -o option can decrease the size of
the reconstructed SCCS file. It can also alter the shape of the delta tree of the origi-
nal file.
-s This option causes comb to generate a shell procedure which, when run, produces a
report giving, for each file: the file name, size (in blocks) after combining, original
size (also in blocks), and percentage change computed by:
100 × (original − combined) / original
It is recommended that this option be used before any
SCCS files are actually com-
bined to determine exactly how much space is saved by the combining process.
If no options are specified,
comb preserves only leaf deltas and the minimal number of ancestors needed
to preserve the tree.
EXTERNAL INFLUENCES
International Code Set Support
Single- and multi-byte character code sets are supported.
DIAGNOSTICS
Use sccshelp (1) for explanations.
EXAMPLES
The command:
comb -c1.1,1.3,1.6 s.document > save_file
creates a shell script named save_file, which if executed, creates a new s.document using only the
deltas 1.1, 1.3,and 1.6 from the old s.document. The script overwrites the old s.document; thus,
it might be wise to copy the original elsewhere. Here is an example of typical technique:
cp s.document s.save
comb -c1.1,1.3,1.6 s.document > save_file
sh save_file
WARNINGS
comb may rearrange the shape of the tree of deltas. Combining files may or may not save space; in fact,
it is possible for the reconstructed file to actually be larger than the original.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1