comb(1)comb(1)NAMEcomb - combine SCCS deltas
SID] list] file ...
The 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, 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 and unreadable files are silently ignored. If
a name of is given, the standard input is read; each line of the stan‐
dard input is taken to be the name of an SCCS file to be processed;
non-SCCS files and unreadable files are silently ignored. The gener‐
ated shell procedure is written on the standard output.
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.
The SCCS IDentification string (SID) of the oldest
delta to be preserved. All older deltas are dis‐
carded in the reconstructed file.
A list of deltas to be preserved (see get(1) for
the syntax of a list). All other deltas are dis‐
For each 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 option can decrease the size of the
reconstructed SCCS file. It can also alter the
shape of the delta tree of the original file.
This option causes
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 com‐
100 × (original − combined) / original
It is recommended that this option be used before
any SCCS files are actually combined to determine
exactly how much space is saved by the combining
If no options are specified, preserves only leaf deltas and the minimal
number of ancestors needed to preserve the tree.
International Code Set Support
Single- and multi-byte character code sets are supported.
Use sccshelp(1) for explanations.
creates a shell script named which if executed, creates a new using
only the deltas from the old The script overwrites the old thus, it
might be wise to copy the original elsewhere. Here is an example of
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.
SEE ALSOadmin(1), delta(1), get(1), sccshelp(1), prs(1), sh(1), sccsfile(4).