c
compress(1) | compress(1) |
| uncompress |
Print the current version and compile options onto the standard error. | |
Specify the maximum number of bits the compress algorithm will use. The | |
| default is 16 and the range can be any integer between 9 and 16. |
compress uses the modi®ed
After the maxbits limit is attained, compress periodically checks the compression ratio. If it is increas- ing, compress continues to use the existing code dictionary. However, if the compression ratio is decreasing, compress discards the table of substrings and rebuilds it from scratch. This allows the algorithm to adapt to the next "block" of the ®le.
Note that the
Access Control Lists
compress retains a ®le's access control list when compressing and expanding data.
EXTERNAL INFLUENCES
Environment Variables
LC_MESSAGES determines the language in which messages are displayed.
If LC_MESSAGES is not speci®ed in the environment or is set to the empty string, the value of LANG is used as a default for each unspeci®ed or empty variable. If LANG is not speci®ed or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG.
If any internationalization variable contains an invalid setting, compress, uncompress, and zcat behave as if all internationalization variables are set to "C". See environ(5).
International Code Set Support
Single- and
RETURN VALUE
These commands return the following values upon completion:
0Completed successfully.
2Last ®le is larger after (attempted) compression.
1An error occurred.
DIAGNOSTICS
Usage: compress
Invalid options were speci®ed on the command line.
Missing maxbits
maxbits must follow
file: not in compressed format
The ®le speci®ed to uncompress has not been compressed.
file: compressed with xxbits, can only handle yybits
®le was compressed by a program that could deal with a higher value of maxbits than the compress code on this machine. Recompress the ®le with a lower value of maxbits.
file: already has .Z suffix
The ®le is assumed to be already compressed. Rename the ®le and try again.
file: filename too long to tack on .Z
The output ®le name, which is the source ®le name with a .Z extension, is too long for the ®le system on which the source ®le resides. Make the source ®le name shorter and try again.
file already exists; do you wish to overwrite (y or n)?
Respond y if you want the output to replace the existing ®le; otherwise, respond n.
Section 1−110 | − 2 − |