z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

compress
Options
Localization
Exit Values
After attaining the bits limit, compress periodically checks the compression ratio. If
it is increasing, compress continues to use the existing code dictionary. However, if
the compression ratio decreases, compress discards the table of substrings and
rebuilds it from scratch. This allows the algorithm to compensate for files, such as
archives, where individual components have different information content profiles.
–b bits
Limits the maximum number of bits of compression to bits. The value bits
can be an integer from 9 to 16. The default is 16.
–c Writes the output to stdout. When you use this option, you can only specify
one file on the command line.
–D Allows an extra degree of compression to be done for files such as sorted
dictionaries where subsequent lines normally have many characters in
common with the preceding line.
–d Decompresses argument files instead of compressing them. This works by
overlaying the compress program with the uncompress program. For this
to work, uncompress must be available somewhere in your search path
(given by the PATH environment variable). Decompressing files this way is
slower than calling uncompress directly.
–f Forces compression even if the resulting file is larger or the output file
already exists. When you do not specify this option, files which are larger
after compression are not compressed. compress does not print an error
message if this happens.
–V Prints the version number of compress.
–v Prints statistics giving the amount of compression achieved. Statistics give
the name of each file compressed and the compression ratio, expressed as
a percentage. If the file resulting from compression is larger than the
original, the compression ratio is negative.
compress uses the following localization environment variables:
v LANG
v LC_ALL
v LC_CTYPE
v LC_MESSAGES
v NLSPATH
See Appendix F for more information.
0 Successful completion
1 Failure due to one of the following:
v Missing number of bits after the –b option
v Incorrect number of bits specified
v Failed to execute uncompress
v Unknown option
v Dictionary option—same count of string exceeded
v Output path or file name too long
v Cannot stat file
144 z/OS V1R9.0 UNIX System Services Command Reference