IO::Unc...:UnLzip(3)

📦

version 2.217 · 11 versions

✨ NAME ✨

okay so bestie, welcome to IO::Unc...:UnLzip(3) 💖 — this is IO::Uncompress::UnLzip, and its whole entire job is reading lzip files/buffers. that's it, that's the vibe.

✨ SYNOPSIS ✨

here's the whole menu, no cap:

use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

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

my $z = IO::Uncompress::UnLzip->new( $input [OPTS] )
    or die "unlzip failed: $UnLzipError\n";

$status = $z->read($buffer)
$status = $z->read($buffer, $length)
$status = $z->read($buffer, $length, $offset)
$line = $z->getline()
$char = $z->getc()
$char = $z->ungetc()
$char = $z->opened()

$data = $z->trailingData()
$status = $z->nextStream()
$data = $z->getHeaderInfo()
$z->tell()
$z->seek($position, $whence)
$z->binmode()
$z->fileno()
$z->eof()
$z->close()

$UnLzipError ;

# IO::File mode

<$z>
read($z, $buffer);
read($z, $buffer, $length);
read($z, $buffer, $length, $offset);
tell($z)
seek($z, $position, $whence)
binmode($z)
fileno($z)
eof($z)
close($z)

✨ DESCRIPTION ✨

so this module hands you a Perl interface that lets you read lzma files/buffers. 🦋

and if you're here trying to write lzip files/buffers? wrong page, babe — go hang out with its companion module, IO::Compress::Lzip. 🎀

💖 Functional Interface 💖

there's a top-level function called unlzip that does the "one-shot" thing — uncompressing straight between buffers and/or files, no extra steps. and if you want finer control over the whole uncompression process, scroll on down to the "OO Interface" section. ✨

use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

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

heads up: the functional interface needs Perl5.005 or better. no ancient perls allowed, sorry bestie 💅

🌸 `unlzip $input_filename_or_reference => $output_filename_or_reference [, OPTS]`

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

The `$input_filename_or_reference` parameter

this one defines where the compressed data comes from. it can take one of these forms:

A filename — if $input_filename_or_reference is a simple scalar, it's assumed to be a filename. the file gets opened for reading, and the input data is read out of it.
A filehandle — if $input_filename_or_reference is a filehandle, the input data gets read from it. and psst: the string '-' works as an alias for standard input. 🫶
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, one at a time, in turn.
- the complete array gets walked first to make sure it only contains valid filenames before any data is uncompressed. safety first, always. ✨
An Input FileGlob string — if $input_filename_or_reference is a string delimited by the characters < and >, unlzip will assume 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? undef gets returned. that's it. 💀

The `$output_filename_or_reference` parameter

this one controls where the uncompressed data goes. it can take one of these forms:

A filename — if $output_filename_or_reference is a simple scalar, it's assumed to be a filename. the file gets opened for writing, and the uncompressed data gets written to it.
A filehandle — if $output_filename_or_reference is a filehandle, the uncompressed data gets written to it. and again, '-' is the alias for standard output. 🫶
A scalar reference — if $output_filename_or_reference is a scalar reference, the uncompressed data gets stored in $$output_filename_or_reference.
An Array Reference — if $output_filename_or_reference is an array reference, the uncompressed data gets pushed onto the array.
An Output FileGlob — if $output_filename_or_reference is a string delimited by the characters < and >, unlzip will assume it's an output fileglob string. the output is the list of files that match the fileglob.
- when $output_filename_or_reference is a fileglob string, $input_filename_or_reference must also be a fileglob string. anything else is an error. periodt.
- see File::GlobMapper for more details.

and if $output_filename_or_reference is any other type, undef gets returned. 🙈

📝 Notes

when $input_filename_or_reference maps to multiple compressed files/buffers and $output_filename_or_reference is a single file/buffer, then after uncompression, $output_filename_or_reference will contain a concatenation of all the uncompressed data from each of the input files/buffers. like a lil smoothie of all your data. 🍓

🎀 Optional Parameters 🎀

the optional parameters for the one-shot function unlzip are (for the most part) identical to the ones used with the OO interface defined over in the "Constructor Options" section. the exceptions are listed below, bestie, don't skip them:

"AutoClose => 0|1" — this option applies to any input or output data streams to unlzip that are filehandles.
- if AutoClose is specified, and the value is true, it will result in all input and/or output filehandles being closed once unlzip has completed.
- this parameter defaults to 0.
"BinModeOut => 0|1" — this option is now a no-op. all files will be written in binmode.
"Append => 0|1" — the behaviour of this option depends on the type of output data stream.
- A Buffer — if Append is enabled, all uncompressed data will be append to the end of the output buffer. otherwise the output buffer will be cleared before any uncompressed data is written to it.
- A Filename — if Append is enabled, the file will be opened in append mode. otherwise the contents of the file, if any, will be truncated before any uncompressed data is written to it.
- A Filehandle — if Append is enabled, the filehandle will be positioned to the end of the file via a call to seek before any uncompressed data is written to it. otherwise the file pointer will not be moved.
- when Append is specified, and set to true, it will append all uncompressed data to the output data stream.
- so when the output is a filehandle it will carry out a seek to the eof before writing any uncompressed data. if the output is a filename, it will be opened for appending. if the output is a buffer, all uncompressed data will be appended to the existing buffer.
- conversely, when Append is not specified, or it is present and is set to false, it will operate as follows:
- when the output is a filename, it will truncate the contents of the file before writing any uncompressed data. if the output is a filehandle, its position will not be changed. if the output is a buffer, it will be wiped before any uncompressed data is output.
- defaults to 0.
"MultiStream => 0|1" — if the input file/buffer contains multiple compressed data streams, this option will uncompress the whole lot as a single data stream.
- defaults to 0.
"TrailingData => $scalar" — returns the data, if any, that is present immediately after the compressed data stream once uncompression is complete.
- this option can be used when there is useful information immediately following the compressed data stream, and you don't know the length of the compressed data stream.
- if the input is a buffer, trailingData will return everything from the end of the compressed data stream to the end of the buffer.
- if the input is a filehandle, trailingData will return the data that is left in the filehandle input buffer once the end of the compressed data stream has been reached. you can then use the filehandle to read the rest of the input file. 👑
- don't bother using trailingData if the input is a filename. just don't.
- if you know the length of the compressed data stream before you start uncompressing, you can avoid having to use trailingData by setting the InputLength option.

🌈 OneShot Examples 🌈

okay these are the fun part, the little recipes:

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

use strict ;
use warnings ;
use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

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

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

use strict ;
use warnings ;
use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;
use IO::File ;

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

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

use strict ;
use warnings ;
use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

unlzip '</my/home/*.txt.xz>' => '</my/home/#1.txt>'
    or die "unlzip failed: $UnLzipError\n";

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

use strict ;
use warnings ;
use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

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

🦋 OO Interface 🦋

🎀 Constructor 🎀

okay bestie, here's the constructor format for IO::Uncompress::UnLzip, no cap:

my $z = IO::Uncompress::UnLzip->new( $input [OPTS] )
    or die "IO::Uncompress::UnLzip failed: $UnLzipError\n";

It takes one mandatory parameter, $input, and zero or more OPTS — those are the ones we're about to spill in Constructor Options.

Returns an IO::Uncompress::UnLzip object when it slays, and undef when it doesn't. The variable $UnLzipError will hold an error message if it fails. 💅

If you're running Perl 5.005 or better, the object $z you get back from IO::Uncompress::UnLzip can be used exactly like an IO::File filehandle. That means all the normal input file operations can be done with $z. For example, to read a line from a compressed file/buffer you can use either of these forms:

$line = $z->getline();
$line = <$z>;

Below is a simple example of using the OO interface to read the compressed file "myfile.xz" and write its contents to stdout. ✨

my $filename = "myfile.xz";
my $z = IO::Uncompress::UnLzip->new($filename)
    or die "IO::Uncompress::UnLzip failed: $UnLzipError\n";

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

See EXAMPLES for further examples. 🫶

The mandatory parameter $input is used to determine the source of the compressed data. This parameter can take one of three forms.

📁 A filename

If the $input parameter is a scalar, it is assumed to be a filename. This file will be opened for reading and the compressed data will be read from it. 🍓

🧚 A filehandle

If the $input parameter is a filehandle, the compressed data will be read from it. The string '-' can be used as an alias for standard input. 💜

⭐ A scalar reference

If $input is a scalar reference, the compressed data will be read from $$input. 👑

💅 Constructor Options 💅

The option names defined below are case insensitive and can be optionally prefixed by a '-'. So all of the following are valid:

-AutoClose
-autoclose
AUTOCLOSE
autoclose

OPTS is a combination of the following options:

AutoClose => 0|1 — This option is only valid when the $input parameter is a filehandle. If specified, and the value is true, it will result in the file being closed once either the close method is called or the IO::Uncompress::UnLzip object is destroyed. This parameter defaults to 0. 🎀
MultiStream => 0|1 — Allows multiple concatenated compressed streams to be treated as a single compressed stream. Decompression will stop once either the end of the file/buffer is reached, an error is encountered (premature eof, corrupt compressed data) or the end of a stream is not immediately followed by the start of another stream. This parameter defaults to 0. 🔥
Prime => $string — This option will uncompress the contents of $string before processing the input file/buffer. This option can be useful when the compressed data is embedded in another file/data structure and it is not possible to work out where the compressed data begins without having to read the first few bytes. If this is the case, the uncompression can be primed with these bytes using this option. 💖
Transparent => 0|1 — If this option is set and the input file/buffer is not compressed data, the module will allow reading of it anyway. In addition, if the input file/buffer does contain compressed data and there is non-compressed data immediately following it, setting this option will make this module treat the whole file/buffer as a single data stream. This option defaults to 1. 🌈
BlockSize => $num — When reading the compressed input data, IO::Uncompress::UnLzip will read it in blocks of $num bytes. This option defaults to 4096. 🦋
InputLength => $size — When present this option will limit the number of compressed bytes read from the input file/buffer to $size. This option can be used in the situation where there is useful data directly after the compressed data stream and you know beforehand the exact length of the compressed data stream. This option is mostly used when reading from a filehandle, in which case the file pointer will be left pointing to the first byte directly after the compressed data stream. This option defaults to off. 💀
Append => 0|1 — This option controls what the read method does with uncompressed data. If set to 1, all uncompressed data will be appended to the output parameter of the read method. If set to 0, the contents of the output parameter of the read method will be overwritten by the uncompressed data. Defaults to 0. 🌸
Strict => 0|1 — This option controls whether the extra checks defined below are used when carrying out the decompression. When Strict is on, the extra tests are carried out, when Strict is off they are not. The default for this option is off. 💅

💅 Methods 💅

Okay bestie, this is the main character section — all the methods you can call on your $z object. Let's get into it. ✨

read 💖 (the first one)

Usage is

$status = $z->read($buffer)

Reads a block of compressed data — the size of that compressed block is determined by the Buffer option in the constructor — uncompresses it, and writes any uncompressed data into $buffer. If the Append parameter is set in the constructor, the uncompressed data gets appended to the $buffer parameter. Otherwise $buffer gets overwritten. Periodt.

Returns the number of uncompressed bytes written to $buffer, zero if eof, or a negative number on error. Slay.

read ✨ (the second one, with length)

Usage is

$status = $z->read($buffer, $length)
$status = $z->read($buffer, $length, $offset)

$status = read($z, $buffer, $length)
$status = read($z, $buffer, $length, $offset)

Attempt to read $length bytes of uncompressed data into $buffer. It's giving precision.

The main difference between this form of the read method and the previous one is that this one will attempt to return exactly $length bytes. The only circumstances where it won't? If end-of-file or an IO error is encountered. That's the tea.

Returns the number of uncompressed bytes written to $buffer, zero if eof, or a negative number on error. No cap.

getline 🌸

Usage is

$line = $z->getline()
$line = <$z>

Reads a single line. Simple as that.

This method fully supports the use of the variable $/ (or $INPUT_RECORD_SEPARATOR or $RS when English is in use) to determine what constitutes an end of line. Paragraph mode, record mode and file slurp mode are all supported. Versatile queen. 👑

getc 🦋

Usage is

$char = $z->getc()

Read a single character. One little character, bestie. 🫶

ungetc 💜

Usage is

$char = $z->ungetc($string)

That's the whole method. Iconic.

getHeaderInfo 🎀

Usage is

$hdr  = $z->getHeaderInfo();
@hdrs = $z->getHeaderInfo();

This method returns either a hash reference (in scalar context) or a list of hash references (in array context) that contains information about each of the header fields in the compressed data stream(s). Header detective vibes. 🔍

tell 💅

Usage is

$z->tell()
tell $z

Returns the uncompressed file offset. Where you at? Now you know.

eof ⭐

Usage is

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

Returns true if the end of the compressed input stream has been reached. You've hit the end, bestie. 🛑

seek 🧚

Usage is

$z->seek($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 input file/buffer. It is a fatal error to attempt to seek backward. So don't even try it, okay? ⚠️

Note that the implementation of seek in this module does not provide true random access to a compressed file/buffer. It works by uncompressing data from the current offset in the file/buffer until it reaches the uncompressed offset specified in the parameters to seek. For very small files this may be acceptable behaviour. For large files it may cause an unacceptable delay. Just a heads up, bestie.

The $whence parameter takes one of the usual values, namely SEEK_SET, SEEK_CUR or SEEK_END. Standard seek energy.

Returns 1 on success, 0 on failure. Good luck.

binmode 🌈

Usage is

$z->binmode
binmode $z ;

This is a noop provided for completeness. Literally does nothing, but it's here for the aesthetic. 💅

opened 👑

Usage is

$z->opened()

Returns true if the object currently refers to an opened file/buffer. Is it open? Yes or no. Simple.

autoflush 💖

Usage is

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. Flush it out, bestie. 🚽 (jk, but also literally)

If $z is associated with a buffer, this method has no effect and always returns undef. Buffer says nope.

Note that the special variable $| cannot be used to set or retrieve the autoflush setting. Don't try it. 🚫

input_line_number 🔢

Usage is

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

Returns the current uncompressed line number. If EXPR is present it has the effect of setting the line number. Note that setting the line number does not change the current position within the file/buffer being read. It's just a number, not a teleport. ✨

The contents of $/ are used to determine what constitutes a line terminator. Line terminator tea.

fileno 📁

Usage is

$z->fileno()
fileno($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. Gone, reduced to atoms. 💀

If the $z object is associated with a buffer, this method will return undef. No file descriptor for buffers, sorry.

close 🚪

Usage is

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

Closes the output file/buffer. Bye bye. 👋

For most versions of Perl this method will be automatically invoked if the IO::Uncompress::UnLzip 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. Perl being extra, as usual.

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. Do it yourself, bestie. Trust.

Returns true on success, otherwise 0. Success or flop.

If the AutoClose option has been enabled when the IO::Uncompress::UnLzip object was created, and the object is associated with a file, the underlying file will also be closed. Double close, double slay.

nextStream 🌊

Usage is

my $status = $z->nextStream();

Skips to the next compressed data stream in the input file/buffer. If a new compressed data stream is found, the eof marker will be cleared and $. will be reset to 0. Fresh stream, fresh me. ✨

Returns 1 if a new stream was found, 0 if none was found, and -1 if an error was encountered. Numbers don't lie.

trailingData 🧵

Usage is

my $data = $z->trailingData();

Returns the data, if any, that is present immediately after the compressed data stream once uncompression is complete. It only makes sense to call this method once the end of the compressed data stream has been encountered. After the end, there might be extra. 👀

This option can be used when there is useful information immediately following the compressed data stream, and you don't know the length of the compressed data stream. Mystery data? Say less.

If the input is a buffer, trailingData will return everything from the end of the compressed data stream to the end of the buffer. Buffer leftovers, served fresh.

If the input is a filehandle, trailingData will return the data that is left in the filehandle input buffer once the end of the compressed data stream has been reached. You can then use the filehandle to read the rest of the input file. Filehandle said "I'll take it from here."

Don't bother using trailingData if the input is a filename. Just don't, bestie.

If you know the length of the compressed data stream before you start uncompressing, you can avoid having to use trailingData by setting the InputLength option in the constructor. Big brain move. 🧠

Importing 🫶

No symbolic constants are required by IO::Uncompress::UnLzip at present. Chill.

:all Imports unlzip and $UnLzipError. Same as doing this

use IO::Uncompress::UnLzip qw(unlzip $UnLzipError) ;

Copy, paste, slay.

✨ EXAMPLES ✨

No examples listed in this section, bestie. Just the heading holding space. Sometimes the real example is the friends we made along the way. 💖

💌 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>. They wanna hear from you. 🫶

👀 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::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzip, 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

So many modules, so little time. ✨

✍️ AUTHOR ✍️

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

📜 MODIFICATION HISTORY 📜

See the Changes file. History is history.

⚖️ COPYRIGHT AND LICENSE ⚖️

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Free as in freedom, bestie. 🕊️

Okay that's the whole manual page, bestie. This was perl v5.42.0, dated 2026-02-01, from IO::Unc...:UnLzip(3). 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::Unc...:UnLzip(3)

✨ NAME ✨

✨ SYNOPSIS ✨

✨ DESCRIPTION ✨

💖 Functional Interface 💖

🌸 unlzip $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 🌈

🦋 OO Interface 🦋

🎀 Constructor 🎀

📁 A filename

🧚 A filehandle

⭐ A scalar reference

💅 Constructor Options 💅

💅 Methods 💅

read 💖 (the first one)

read ✨ (the second one, with length)

getline 🌸

getc 🦋

ungetc 💜

getHeaderInfo 🎀

tell 💅

eof ⭐

seek 🧚

binmode 🌈

opened 👑

autoflush 💖

input_line_number 🔢

fileno 📁

close 🚪

nextStream 🌊

trailingData 🧵

Importing 🫶

✨ EXAMPLES ✨

💌 SUPPORT 💌

👀 SEE ALSO 👀

✍️ AUTHOR ✍️

📜 MODIFICATION HISTORY 📜

⚖️ COPYRIGHT AND LICENSE ⚖️

🌸 `unlzip $input_filename_or_reference => $output_filename_or_reference [, OPTS]`

The `$input_filename_or_reference` parameter

The `$output_filename_or_reference` parameter