GZIP(1) GZIP(1)
NAME
gzip, gunzip, bzip2, bunzip2, zip, unzip, - compress and
expand data
SYNOPSIS
gzip [-cvD[1-9]] [file ...]
gunzip [-ctTvD] [file ...]
bzip2 [-cvD[1-9]] [file ...]
bunzip2 [-cvD] [file ...]
zip [-vD[1-9]] [-f zipfile] file [...]
unzip [-cistTvD] [-f zipfile] [file ...]
DESCRIPTION
Gzip encodes files with a hybrid Lempel-Ziv 1977 and Huffman
compression algorithm known as deflate. Most of the time,
the resulting file is smaller, and will never be much big-
ger. Output files are named by taking the last path element
of each file argument and appending .gz; if the resulting
name ends with .tar.gz, it is converted to .tgz instead.
Gunzip reverses the process. Its output files are named by
taking the last path element of each file argument, convert-
ing .tgz to .tar.gz, and stripping any .gz; the resulting
name must be different from the original name.
Bzip2 and bunzip2 are similar in interface to gzip and
gunzip, but use a modified Burrows-Wheeler block sorting
compression algorithm. The default suffix for output files
is .bz2, with .tar.bz2 becoming .tbz. Bunzip2 recognizes
the extension .tbz2 as a synonym for .tbz.
Zip encodes the named files and places the results into the
archive zipfile, or the standard output if no file is given.
Unzip extracts files from an archive created by zip. If no
files are named as arguments, all of files in the archive
are extracted. A directory's name implies all recursively
contained files and subdirectories.
None of these programs removes the original files. If the
process fails, the faulty output files are removed.
The options are:
-c Write to standard output rather than creating an
output file.
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GZIP(1) GZIP(1)
-i Convert all archive file names to lower case.
-s Streaming mode. Looks at the file data adjacent
to each compressed file rather than seeking in the
central file directory. This is the mode used by
unzip if no zipfile is specified. If -s is given,
-T is ignored.
-t List matching files in the archive rather than
extracting them.
-T Set the output time to that specified in the
archive.
-1 .. -9 Sets the compression level. -1 is tuned for
speed, -9 for minimal output size. The best com-
promise is -6, the default.
-v Produce more descriptive output. With -t, adds
the uncompressed size in bytes and the modifica-
tion time to the output. Without -t, prints the
names of files on standard error as they are com-
pressed or decompressed.
-D Produce debugging output.
SOURCE
/usr/local/plan9/src/cmd/gzip
/usr/local/plan9/src/cmd/bzip2
SEE ALSO
tar(1), compress(1)
BUGS
Unzip can only extract files which are uncompressed or com-
pressed with the deflate compression scheme. Recent zip
files fall into this category.
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