src/xzdec/xzdec.1

.\"
.\" Author: Lasse Collin
.\"
.\" This file has been put into the public domain.
.\" You can do whatever you want with this file.
.\"
.TH XZDEC 1 "2010-03-07" "Tukaani" "XZ Utils"
.SH NAME
xzdec, lzmadec \- Small .xz and .lzma decompressors
.SH SYNOPSIS
.B xzdec
.RI [ option ]...
.RI [ file ]...
.br
.B lzmadec
.RI [ option ]...
.RI [ file ]...
.SH DESCRIPTION
.B xzdec
is a liblzma-based decompression-only tool for
.B .xz
(and only
.BR .xz )
files.
.B xzdec
is intended to work as a drop-in replacement for
.BR xz (1)
in the most common situations where a script has been written to use
.B "xz \-\-decompress \-\-stdout"
(and possibly a few other commonly used options) to decompress
.B .xz
files.
.B lzmadec
is identical to
.B xzdec
except that
.B lzmadec
supports
.B .lzma
files instead of
.B .xz
files.
.PP
To reduce the size of the executable,
.B xzdec
doesn't support multithreading or localization, and doesn't read options from
.B XZ_OPT
environment variable.
.B xzdec
doesn't support displaying intermediate progress information: sending
.B SIGINFO
to
.B xzdec
does nothing, but sending
.B SIGUSR1
terminates the process instead of displaying progress information.
.SH OPTIONS
.TP
.BR \-d ", " \-\-decompress ", " \-\-uncompress
Ignored for
.BR xz (1)
compatibility.
.B xzdec
supports only decompression.
.TP
.BR \-k ", " \-\-keep
Ignored for
.BR xz (1)
compatibility.
.B xzdec
never creates or removes any files.
.TP
.BR \-c ", " \-\-stdout ", " \-\-to-stdout
Ignored for
.BR xz (1)
compatibility.
.B xzdec
always writes the decompressed data to standard output.
.TP
\fB\-M\fR \fIlimit\fR, \fB\-\-memory=\fIlimit
Set the memory usage
.IR limit .
If this option is specified multiple times, the last one takes effect. The
.I limit
can be specified in multiple ways:
.RS
.IP \(bu 3
The
.I limit
can be an absolute value in bytes. Using an integer suffix like
.B MiB
can be useful. Example:
.B "\-\-memory=80MiB"
.IP \(bu 3
The
.I limit
can be specified as a percentage of physical RAM. Example:
.B "\-\-memory=70%"
.IP \(bu 3
The
.I limit
can be reset back to its default value by setting it to
.BR 0 .
.IP \(bu 3
The memory usage limiting can be effectively disabled by setting
.I limit
to
.BR max .
This isn't recommended. It's usually better to use, for example,
.BR \-\-memory=90% .
.RE
.IP
The current
.I limit
can be seen near the bottom of the output of the
.B \-\-help
option.
.TP
.BR \-q ", " \-\-quiet
Specifying this once does nothing since
.B xzdec
never displays any warnings or notices.
Specify this twice to suppress errors.
.TP
.BR \-Q ", " \-\-no-warn
Ignored for
.BR xz (1)
compatibility.
.B xzdec
never uses the exit status
.BR "2" .
.TP
.BR \-h ", " \-\-help
Display a help message and exit successfully.
.TP
.BR \-V ", " \-\-version
Display the version number of
.B xzdec
and liblzma.
.SH "EXIT STATUS"
.TP
.B 0
All was good.
.TP
.B 1
An error occurred.
.PP
.B xzdec
doesn't have any warning messages like
.BR xz (1)
has, thus the exit status
.B 2
is not used by
.BR xzdec .
.SH NOTES
.B xzdec
and
.B lzmadec
are not really that small. The size can be reduced further by dropping
features from liblzma at compile time, but that shouldn't usually be done
for executables distributed in typical non-embedded operating system
distributions. If you need a truly small
.B .xz
decompressor, consider using XZ Embedded.
.SH "SEE ALSO"
.BR xz (1)
.PP
XZ Embedded: <http://tukaani.org/xz/embedded.html>