IO::Compress::Xz(3)

📦

version 2.217 · 11 versions

💖 IO::Compress::Xz 💖

okay bestie, so this is the manual page for IO::Compress::Xz(3), and it's a User Contributed Perl Documentation situation, and it is long, so buckle up. this is part 1 of 3 🎀

✨ NAME ✨

IO::Compress::Xz — Write xz files/buffers. that's it, that's the whole vibe. it writes xz. iconic.

🌸 SYNOPSIS 🌸

use IO::Compress::Xz qw(xz $XzError) ;

my $status = xz $input => $output [,OPTS]
    or die "xz failed: $XzError\n";

my $z = IO::Compress::Xz->new( $output [,OPTS] )
    or die "xz failed: $XzError\n";

$z->print($string);
$z->printf($format, $string);
$z->write($string);
$z->syswrite($string [, $length, $offset]);
$z->flush();
$z->tell();
$z->eof();
$z->seek($position, $whence);
$z->binmode();
$z->fileno();
$z->opened();
$z->autoflush();
$z->input_line_number();
$z->newStream( [OPTS] );

$z->close() ;

$XzError ;

# IO::File mode

print $z $string;
printf $z $format, $string;
tell $z
eof $z
seek $z, $position, $whence
binmode $z
fileno $z
close $z ;

🦋 DESCRIPTION 🦋

so like. this module gives you a Perl interface that lets you write xz compressed data to files or to a buffer. that's the whole job. she writes. she compresses. she leaves. 💅

and if you're trying to go the other way — like, reading xz files/buffers instead of writing them — you want the companion module, IO::Uncompress::UnXz. that's her sister. different girl, same family. 🫶

💫 Functional Interface 💫

there's a top-level function called xz that does the whole "one-shot" compression thing between buffers and/or files. like, you give her stuff, she gives you compressed stuff, no extra steps. but if you want finer control over the compression process, go look at the "OO Interface" section instead. that's the fancy route. 😌

use IO::Compress::Xz qw(xz $XzError) ;

xz $input_filename_or_reference => $output_filename_or_reference [,OPTS]
    or die "xz failed: $XzError\n";

ngl, the functional interface needs Perl5.005 or better. no ancient Perls allowed, sorry. 🙈

🌟 `xz $input_filename_or_reference => $output_filename_or_reference [, OPTS]` 🌟

xz wants at least two parameters — $input_filename_or_reference and $output_filename_or_reference — plus zero or more optional parameters (those live down in "Optional Parameters", keep scrolling bestie).

🎀 The $input_filename_or_reference parameter 🎀

so $input_filename_or_reference is the thing that defines where the uncompressed data comes from. and she's flexible, she can take any of these forms:

A filename — if $input_filename_or_reference is a simple scalar, it's assumed to be a filename. that file gets opened for reading and the input data gets read from it. easy.
A filehandle — if $input_filename_or_reference is a filehandle, the input data gets read from it. and the string '-' can be used as an alias for standard input. cute right?
A scalar reference — if $input_filename_or_reference is a scalar reference, the input data gets read from $$input_filename_or_reference.
An array reference — if $input_filename_or_reference is an array reference, every element in the array has to be a filename. the input data gets read from each file in turn. and the whole array gets walked to make sure it only contains valid filenames before any data is compressed. she checks first, she doesn't just go in blind. 👑
An Input FileGlob string — if $input_filename_or_reference is a string delimited by the characters < and >, then xz assumes it's an input fileglob string. the input is the list of files that match the fileglob. see File::GlobMapper for more details.

and if $input_filename_or_reference is literally any other type? then undef gets returned. that's it. that's the answer. 💀

🌈 The $output_filename_or_reference parameter 🌈

$output_filename_or_reference is the one that controls where the compressed data goes. and she also has options, because of course she does:

A filename — if $output_filename_or_reference is a simple scalar, it's assumed to be a filename. this file gets opened for writing and the compressed data gets written to it.
A filehandle — if $output_filename_or_reference is a filehandle, the compressed data gets written to it. and the string '-' can be used as an alias for standard output.
A scalar reference — if $output_filename_or_reference is a scalar reference, the compressed data gets stored in $$output_filename_or_reference.
An Array Reference — if $output_filename_or_reference is an array reference, the compressed data gets pushed onto the array.
An Output FileGlob — if $output_filename_or_reference is a string delimited by the characters < and >, then xz assumes it's an output fileglob string. the output is the list of files that match the fileglob. see File::GlobMapper for more details.

⚠️ okay so important: when $output_filename_or_reference is a fileglob string, then $input_filename_or_reference also has to be a fileglob string. anything else is an error. no mixing, bestie, it's giving commitment issues.

and if $output_filename_or_reference is any other type, undef gets returned. same energy as before. 😭

🍓 Notes 🍓

when $input_filename_or_reference maps to multiple files/buffers, but $output_filename_or_reference is a single file/buffer, then the input files/buffers get stored in $output_filename_or_reference as a concatenated series of compressed data streams. so like, one big stack of streams. she stacked them. periodt.

💅 Optional Parameters 💅

the optional parameters for the one-shot function xz are (for the most part) identical to the ones used with the OO interface defined up in the "Constructor Options" section. the exceptions are listed right here:

AutoClose => 0|1 — this one applies to any input or output data streams given to xz that happen to be filehandles. if AutoClose is specified and the value is true, it'll result in all input and/or output filehandles being closed once xz has completed. and it defaults to 0. 💤
BinModeIn => 0|1 — bestie this option is now a no-op. like, nothing happens. all files will be read in binmode regardless. it's retired. she's living her best retired life. 🌴
Append => 0|1 — okay so the behaviour of this one depends on the type of output data stream. let's break it down:
- A Buffer — if Append is enabled, all compressed data gets appended to the end of the output buffer. otherwise, the output buffer gets cleared before any compressed data is written to it.
- A Filename — if Append is enabled, the file gets opened in append mode. otherwise, the contents of the file (if there are any) get truncated before any compressed data is written to it.
- A Filehandle — if Append is enabled, the filehandle gets positioned to the end of the file via a call to seek before any compressed data is written to it. otherwise, the file pointer does not move. stay put. 🧍

so when Append is specified and set to true, it'll append all compressed data to the output data stream. meaning: when the output is a filehandle, it carries out a seek to the eof before writing any compressed data. if the output is a filename, it gets opened for appending. if the output is a buffer, all compressed data gets appended to the existing buffer. slay.

and conversely — when Append is not specified, or it's present and set to false — it operates like this: when the output is a filename, it truncates the contents of the file before writing any compressed data. if the output is a filehandle, its position is not changed. if the output is a buffer, it gets wiped before any compressed data is output. bye bye old data. 🧹

and it defaults to 0.

🧚 Oneshot Examples 🧚

here are a few examples showing off what this module can do. flex time. 🔥

Streaming

this very simple command line example demonstrates the streaming capabilities of the module. the code reads data from STDIN, compresses it, and writes the compressed data to STDOUT.

$ echo hello world | perl -MIO::Compress::Xz=xz -e 'xz \*STDIN => \*STDOUT' >output.xz

and the special filename "-" can be used as a standin for both "\*STDIN" and "\*STDOUT", so the above can be rewritten as:

$ echo hello world | perl -MIO::Compress::Xz=xz -e 'xz "-" => "-"' >output.xz

Compressing a file from the filesystem

to read the contents of the file file1.txt and write the compressed data to the file file1.txt.xz:

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;

my $input = "file1.txt";
xz $input => "$input.xz"
    or die "xz failed: $XzError\n";

Reading from a Filehandle and writing to an in-memory buffer

to read from an existing Perl filehandle, $input, and write the compressed data to a buffer, $buffer:

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;
use IO::File ;

my $input = IO::File->new( "<file1.txt" )
    or die "Cannot open 'file1.txt': $!\n" ;
my $buffer ;
xz $input => \$buffer
    or die "xz failed: $XzError\n";

Compressing multiple files

to compress all files in the directory /my/home that match *.txt and store the compressed data in the same directory:

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;

xz '</my/home/*.txt>' => '<*.xz>'
    or die "xz failed: $XzError\n";

and if you want to compress each file one at a time, this will do the trick:

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;

for my $input ( glob "/my/home/*.txt" )
{
    my $output = "$input.xz" ;
    xz $input => $output
        or die "Error compressing '$input': $XzError\n";
}

okay that's part 1 bestie, more is coming, don't go anywhere 🫶✨

✨ OO Interface ✨

🛠️ Constructor

okay bestie, the constructor format for IO::Compress::Xz is literally this:

my $z = IO::Compress::Xz->new( $output [,OPTS] )
    or die "IO::Compress::Xz failed: $XzError\n";

This constructor takes one mandatory parameter, $output (defined below), and zero or more OPTS, which are defined in Constructor Options. It hands you back an IO::Compress::Xz object on success, and undef on failure. If it fails, $XzError will be holding an error message, periodt.

If you're running Perl 5.005 or better, the object $z you get from IO::Compress::Xz can be used exactly like an IO::File filehandle. That means all normal output file operations can be carried out with $z. For example, to write to a compressed file/buffer you can use either of these forms:

$z->print("hello world\n");
print $z "hello world\n";

Below is a simple example of using the OO interface to create an output file myfile.xz and write some data to it.

my $filename = "myfile.xz";
my $z = IO::Compress::Xz->new($filename)
    or die "IO::Compress::Xz failed: $XzError\n";

$z->print("abcde");
$z->close();

See the Examples for more.

The mandatory parameter $output is used to control the destination of the compressed data. This parameter can take one of these forms.

A filename

If the $output parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it.

A filehandle

If the $output parameter is a filehandle, the compressed data will be written to it. The string '-' can be used as an alias for standard output.

A scalar reference

If $output is a scalar reference, the compressed data will be stored in $$output.

If the $output parameter is any other type, IO::Compress::Xz::new will return undef.

🎀 Constructor Options

OPTS is any combination of zero or more of the following options:

AutoClose => 0|1 — this option is only valid when the $output parameter is a filehandle. If specified, and the value is true, it will result in the $output being closed once either the close method is called or the IO::Compress::Xz object is destroyed. This parameter defaults to 0.
Append => 0|1 — opens $output in append mode. The behaviour of this option is dependent on the type of $output.
- A Buffer — if $output is a buffer and Append is enabled, all compressed data will be append to the end of $output. Otherwise $output will be cleared before any data is written to it.
- A Filename — if $output is a filename and Append is enabled, the file will be opened in append mode. Otherwise the contents of the file, if any, will be truncated before any compressed data is written to it.
- A Filehandle — if $output is a filehandle, the file pointer will be positioned to the end of the file via a call to seek before any compressed data is written to it. Otherwise the file pointer will not be moved. This parameter defaults to 0.
Preset => $preset — used to choose the compression preset. Valid values are 0-9 and LZMA_PRESET_DEFAULT. 0 is the fastest compression with the lowest memory usage and the lowest compression. 9 is the slowest compression with the highest memory usage but with the best compression. Defaults to LZMA_PRESET_DEFAULT (6).
Extreme => 0|1 — makes the compression a lot slower, but a small compression gain. Defaults to 0.
Check => $check — used to specify the integrity check used in the xz data stream. Valid values are LZMA_CHECK_NONE, LZMA_CHECK_CRC32, LZMA_CHECK_CRC64, LZMA_CHECK_SHA256. Defaults to LZMA_CHECK_CRC32.
Strict => 0|1 — this is a placeholder option.

🌈 Examples

Streaming

This very simple command line example demonstrates the streaming capabilities of the module. The code reads data from STDIN or all the files given on the commandline, compresses it, and writes the compressed data to STDOUT.

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;

my $z = IO::Compress::Xz->new("-", Stream => 1)
    or die "IO::Compress::Xz failed: $XzError\n";

while (<>) {
    $z->print("abcde");
}
$z->close();

Note the use of "-" to means "STDOUT". Alternatively you can use "\*STDOUT".

Compressing a file from the filesystem

To read the contents of the file file1.txt and write the compressed data to the file file1.txt.xz there are a few options.

Start by creating the compression object and opening the input file:

use strict ;
use warnings ;
use IO::Compress::Xz qw(xz $XzError) ;

my $input = "file1.txt";
my $z = IO::Compress::Xz->new("file1.txt.xz")
    or die "IO::Compress::Xz failed: $XzError\n";

# open the input file
open my $fh, "<", "file1.txt"
    or die "Cannot open file1.txt: $!\n";

# loop through the input file & write to the compressed file
while (<$fh>) {
    $z->print($_);
}

# not forgetting to close the compressed file
$z->close();

💅 Methods

print

Usage is

$z->print($data)
print $z $data

Compresses and outputs the contents of the $data parameter. This has the same behaviour as the print built-in. Returns true if successful.

printf

Usage is

$z->printf($format, $data)
printf $z $format, $data

Compresses and outputs the contents of the $data parameter. Returns true if successful.

syswrite

Usage is

$z->syswrite $data
$z->syswrite $data, $length
$z->syswrite $data, $length, $offset

Compresses and outputs the contents of the $data parameter. Returns the number of uncompressed bytes written, or undef if unsuccessful.

write

Usage is

$z->write $data
$z->write $data, $length
$z->write $data, $length, $offset

Compresses and outputs the contents of the $data parameter. Returns the number of uncompressed bytes written, or undef if unsuccessful.

flush

Usage is

$z->flush;

Flushes any pending compressed data to the output file/buffer. Returns true on success.

tell

Usage is

$z->tell()
tell $z

Returns the uncompressed file offset.

eof

Usage is

$z->eof();
eof($z);

Returns true if the close method has been called.

seek

$z->seek($position, $whence);
seek($z, $position, $whence);

Provides a sub-set of the seek functionality, with the restriction that it is only legal to seek forward in the output file/buffer. It is a fatal error to attempt to seek backward. Empty parts of the file/buffer will have NULL (0x00) bytes written to them. The $whence parameter takes one the usual values, namely SEEK_SET, SEEK_CUR or SEEK_END. Returns 1 on success, 0 on failure.

binmode

Usage is

$z->binmode
binmode $z ;

This is a noop provided for completeness.

opened

$z->opened()

Returns true if the object currently refers to a opened file/buffer.

autoflush

my $prev = $z->autoflush()
my $prev = $z->autoflush(EXPR)

If the $z object is associated with a file or a filehandle, this method returns the current autoflush setting for the underlying filehandle. If EXPR is present, and is non-zero, it will enable flushing after every write/print operation. If $z is associated with a buffer, this method has no effect and always returns undef. Note that the special variable $| cannot be used to set or retrieve the autoflush setting.

input_line_number

$z->input_line_number()
$z->input_line_number(EXPR)

This method always returns undef when compressing.

fileno

$z->fileno()
fileno($z)

If the $z object is associated with a file or a filehandle, fileno will return the underlying file descriptor. Once the close method is called fileno will return undef. If the $z object is associated with a buffer, this method will return undef.

close

$z->close() ;
close $z ;

Flushes any pending compressed data and then closes the output file/buffer. For most versions of Perl this method will be automatically invoked if the IO::Compress::Xz object is destroyed (either explicitly or by the variable with the reference to the object going out of scope). The exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In these cases, the close method will be called automatically, but not until global destruction of all live objects when the program is terminating. Therefore, if you want your scripts to be able to run on all versions of Perl, you should call close explicitly and not rely on automatic closing. Returns true on success, otherwise 0. If the AutoClose option has been enabled when the IO::Compress::Xz object was created, and the object is associated with a file, the underlying file will also be closed.

newStream([OPTS])

Usage is

$z->newStream( [OPTS] )

Closes the current compressed data stream and starts a new one. OPTS consists of any of the options that are available when creating the $z object. See the Constructor Options section for more details.

✨ Importing ✨

No symbolic constants are required by IO::Compress::Xz at present.

:all Imports xz and $XzError. Same as doing this

use IO::Compress::Xz qw(xz $XzError) ;

🌈 EXAMPLES

💬 SUPPORT

General feedback/questions/bug reports should be sent to https://github.com/pmqs/IO-Compress-Lzma/issues (preferred) or https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress-Lzma.

👀 SEE ALSO

Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Uncompress::UnXz, IO::Compress::Lzip, IO::Uncompress::UnLzip, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Compress::Zstd, IO::Uncompress::UnZstd, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress

IO::Compress::FAQ

File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib

💖 AUTHOR

This module was written by Paul Marquess, "pmqs@cpan.org".

📜 MODIFICATION HISTORY

See the Changes file.

💖 COPYRIGHT AND LICENSE 💖

okay so legal bit, bestie, but like... it's actually important so read it, no skimming 🙈

And here's the vibe:

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. 💅

That's it. Redistribute it, remix it, pass it around, do your thing — just keep it under the exact same terms as Perl itself. Same energy, same rules, no cap. 👑

This page is from perl v5.42.0 and it got its lil glow-up on 2026-02-01, and you're looking at the IO::Compress::Xz(3) manual page. 🦋

okay that's literally the whole thing, go compress something, mwah 💋🎀🌸

📦 where this page comes from

fedora 44: perl-IO-Compress-Lzma 2.217-1.fc44 · GPL-1.0-or-later OR Artistic-1.0-Perl
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-14: a language model's rewrite of the original, under its terms

IO::Compress::Xz(3)

💖 IO::Compress::Xz 💖

✨ NAME ✨

🌸 SYNOPSIS 🌸

🦋 DESCRIPTION 🦋

💫 Functional Interface 💫

🌟 xz $input_filename_or_reference => $output_filename_or_reference [, OPTS] 🌟

🎀 The $input_filename_or_reference parameter 🎀

🌈 The $output_filename_or_reference parameter 🌈

🍓 Notes 🍓

💅 Optional Parameters 💅

🧚 Oneshot Examples 🧚

Streaming

Compressing a file from the filesystem

Reading from a Filehandle and writing to an in-memory buffer

Compressing multiple files

✨ OO Interface ✨

🛠️ Constructor

A filename

A filehandle

A scalar reference

🎀 Constructor Options

🌈 Examples

Streaming

Compressing a file from the filesystem

💅 Methods

print

printf

syswrite

write

flush

tell

eof

seek

binmode

opened

autoflush

input_line_number

fileno

close

newStream([OPTS])

✨ Importing ✨

🌈 EXAMPLES

💬 SUPPORT

👀 SEE ALSO

💖 AUTHOR

📜 MODIFICATION HISTORY

💖 COPYRIGHT AND LICENSE 💖

🌟 `xz $input_filename_or_reference => $output_filename_or_reference [, OPTS]` 🌟