TH GZIP 1
SH NAME
gzip, gunzip, bzip2, bunzip2, zip, unzip, \- compress and expand data
SH SYNOPSIS
B gzip
RB [ -cvD [ 1-9 ]]
RI [ file
BR ... ]
PP
B gunzip
RB [ -ctTvD ]
RI [ file
BR ... ]
PP
B bzip2
RB [ -cvD [ 1-9 ]]
RI [ file
BR ... ]
PP
B bunzip2
RB [ -cvD ]
RI [ file
BR ... ]
PP
B zip
RB [ -vD [ 1-9 ]]
RB [ -f
IR zipfile ]
I file
RB [ ... ]
PP
B unzip
RB [ -cistTvD ]
RB [ -f
IR zipfile ]
IR [ file
BR ... ]
SH DESCRIPTION
PP
I Gzip
encodes files with a hybrid Lempel-Ziv 1977 and Huffman compression algorithm
known as
BR deflate .
Most of the time, the resulting file is smaller,
and will never be much bigger.
Output files are named by taking the last path element of each file argument
and appending
BR .gz ;
if the resulting name ends with
BR .tar.gz ,
it is converted to
B .tgz
instead.
I Gunzip
reverses the process.
Its output files are named by taking the last path element of each file argument,
converting
B .tgz
to
BR .tar.gz ,
and stripping any
BR .gz ;
the resulting name must be different from the original name.
PP
I Bzip2
and
I bunzip2
are similar in interface to
I gzip
and
IR gunzip ,
but use a modified Burrows-Wheeler block sorting
compression algorithm.
The default suffix for output files is
BR .bz2 ,
with
B .tar.bz2
becoming
BR .tbz .
I Bunzip2
recognizes the extension
B .tbz2
as a synonym for
BR .tbz .
PP
I Zip
encodes the named files and places the results into the archive
IR zipfile ,
or the standard output if no file is given.
I Unzip
extracts files from an archive created by
IR 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.
PP
None of these programs removes the original files.
If the process fails, the faulty output files are removed.
PP
The options are:
TP 1i
B -c
Write to standard output rather than creating an output file.
TP
B -i
Convert all archive file names to lower case.
TP
B -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
I unzip
if no
I zipfile
is specified.
If
B -s
is given,
B -T
is ignored.
TP
B -t
List matching files in the archive rather than extracting them.
TP
B -T
Set the output time to that specified in the archive.
TP
BR -1 " .. " -9
Sets the compression level.
B -1
is tuned for speed,
B -9
for minimal output size.
The best compromise is
BR -6 ,
the default.
TP
B -v
Produce more descriptive output.
With
BR -t ,
adds the uncompressed size in bytes and the modification time to the output.
Without
BR -t ,
prints the names of files on standard error as they are compressed or decompressed.
TP
B -D
Produce debugging output.
SH SOURCE
B /sys/src/cmd/gzip
br
B /sys/src/cmd/bzip2
SH SEE ALSO
IR tar (1),
IR compress (1)
SH BUGS
I Unzip
can only extract files which are uncompressed or compressed
with the
B deflate
compression scheme. Recent zip files fall into this category.
