Name
comb - combine SCCS deltas
Syntax
comb -o -s [-pSID] [-clist] files
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 keyletter 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 (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 input is taken to be the name of an
SCCS file to be processed; non-SCCS files and unreadable
files are silently ignored. The generated shell procedure
is written on the standard output.
The keyletter arguments are as follows. Each is explained
as though only one named file is to be processed, but the
effects of any keyletter 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, otherwise the
reconstructed file would be accessed at the most
recent ancestor. Use of the -o keyletter may
decrease the size of the reconstructed SCCS file.
It may also alter the shape of the delta tree of
the original file.
-pSID The SCCS identification string (SID) 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.
-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 information.
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.
-clist
This command causes the existing deltas in the subject
file to be combined. It then overwrites the subject
file with the new combined 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 keyletter 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.
See Also
admin(CP), delta(CP), get(CP), prs(CP), sccsfile(F) sh(C)
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.
(printed 6/18/89)