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Source code changes of the file "compress.1" between
ncompress-4.2.4.4.tar.gz and ncompress-4.2.4.5.tar.gz

About: (N)compress is an improved version of compress 4.1. Compress is a fast, simple LZW file compressor (but has a relatively low compression rate).

compress.1  (ncompress-4.2.4.4):compress.1  (ncompress-4.2.4.5)
COMPRESS(1) General Commands Manual COMPRESS(1) COMPRESS(1) General Commands Manual COMPRESS(1)
NAME NAME
compress, uncompress, zcat - compress and expand data compress, uncompress, zcat - compress and expand data
SYNOPSIS SYNOPSIS
compress [ -f ] [ -v ] [ -c ] [ -V ] [ -r ] [ -b bits ] [ name ... ] compress [ -f ] [ -v ] [ -c ] [ -V ] [ -r ] [ -b bits ] [ -- ] [ name ...
uncompress [ -f ] [ -v ] [ -c ] [ -V ] [ name ... ] ]
zcat [ -V ] [ name ... ] uncompress [ -f ] [ -v ] [ -c ] [ -V ] [ -- ] [ name ... ]
zcat [ -V ] [ -- ] [ name ... ]
DESCRIPTION DESCRIPTION
Compress reduces the size of the named files using adaptive Lempel-Ziv c oding. Whenever possible, each Compress reduces the size of the named files using adaptive Lempel-Ziv c oding. Whenever possible, each
file is replaced by one with the extension .Z, while keeping the same own ership modes, access and modi- file is replaced by one with the extension .Z, while keeping the same own ership modes, access and modi-
fication times. If no files are specified, the standard input is com pressed to the standard output. fication times. If no files are specified, the standard input is com pressed to the standard output.
Compress will only attempt to compress regular files. In particular, it will ignore symbolic links. If Compress will only attempt to compress regular files. In particular, it will ignore symbolic links. If
a file has multiple hard links, compress will refuse to compress it unles s the -f flag is given. a file has multiple hard links, compress will refuse to compress it unles s the -f flag is given.
If -f is not given and compress is run in the foreground, the user is pro mpted as to whether an existing If -f is not given and compress is run in the foreground, the user is pro mpted as to whether an existing
file should be overwritten. file should be overwritten.
skipping to change at line 63 skipping to change at line 63
is encoded within the output, along with a magic number to ensure that ne ither decompression of random is encoded within the output, along with a magic number to ensure that ne ither decompression of random
data nor recompression of compressed data is attempted. data nor recompression of compressed data is attempted.
The amount of compression obtained depends on the size of the input, t he number of bits per code, and The amount of compression obtained depends on the size of the input, t he number of bits per code, and
the distribution of common substrings. Typically, text such as source co de or English is reduced by the distribution of common substrings. Typically, text such as source co de or English is reduced by
50-60%. Compression is generally much better than that achieved by Huffm an coding (as used in pack), or 50-60%. Compression is generally much better than that achieved by Huffm an coding (as used in pack), or
adaptive Huffman coding (compact), and takes less time to compute. adaptive Huffman coding (compact), and takes less time to compute.
Under the -v option, a message is printed yielding the percentage of redu ction for each file compressed. Under the -v option, a message is printed yielding the percentage of redu ction for each file compressed.
-- may be used to halt option parsing and force all remaining arguments t
o be treated as paths.
DIAGNOSTICS DIAGNOSTICS
Exit status is normally 0; if the last file is larger after (attempted) c ompression, the status is 2; if Exit status is normally 0; if the last file is larger after (attempted) c ompression, the status is 2; if
an error occurs, exit status is 1. an error occurs, exit status is 1.
Usage: compress [-dfvcVr] [-b maxbits] [file ...] Usage: compress [-dfvcVr] [-b maxbits] [file ...]
Invalid options were specified on the command line. Invalid options were specified on the command line.
Missing maxbits Missing maxbits
Maxbits must follow -b. Maxbits must follow -b.
file: not in compressed format file: not in compressed format
The file specified to uncompress has not been compressed. The file specified to uncompress has not been compressed.
 End of changes. 2 change blocks. 
3 lines changed or deleted 7 lines changed or added

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