Provided by: squashfs-tools_4.6.1-1_amd64 
NAME
unsquashfs - tool to uncompress, extract and list squashfs filesystems
SYNOPSIS
unsquashfs [OPTIONS] FILESYSTEM [files to extract or exclude (with -excludes) or cat (with
-cat )]
DESCRIPTION
Squashfs is a highly compressed read-only filesystem for Linux. It uses either
gzip/xz/lzo/lz4/zstd compression to compress both files, inodes and directories. Inodes
in the system are very small and all blocks are packed to minimise data overhead. Block
sizes greater than 4K are supported up to a maximum of 1Mbytes (default block size 128K).
Squashfs is intended for general read-only filesystem use, for archival use (i.e. in cases
where a .tar.gz file may be used), and in constrained block device/memory systems (e.g.
embedded systems) where low overhead is needed.
OPTIONS
Filesystem extraction (filtering) options:
-d PATHNAME, -dest PATHNAME
extract to PATHNAME, default "squashfs-root". This option also sets the prefix used
when listing the filesystem.
-max LEVELS, -max-depth LEVELS
descend at most LEVELS of directories when extracting.
-excludes
treat files on command line as exclude files.
-ex, -exclude-list
list of files to be excluded, terminated with ; e.g. file1 file2 ;.
-extract-file FILE
list of directories or files to extract. One per line.
-exclude-file FILE
list of directories or files to exclude. One per line.
-match abort if any extract file does not match on anything, and can not be resolved.
Implies -missing-symlinks and -no-wildcards.
-follow, -follow-symlinks
follow symlinks in extract files, and add all files/symlinks needed to resolve
extract file. Implies -no-wildcards.
-missing, -missing-symlinks
Unsquashfs will abort if any symlink can't be resolved in -follow-symlinks.
-no-wild, -no-wildcards
do not use wildcard matching in extract and exclude names.
-r, -regex
treat extract names as POSIX regular expressions rather than use the default shell
wildcard expansion (globbing).
-all TIME, -all-time TIME
set all file timestamps to TIME, rather than the time stored in the filesystem
inode. TIME can be an unsigned 32-bit int indicating seconds since the epoch
(1970-01-01) or a string value which is passed to the "date" command to parse. Any
string value which the date command recognises can be used such as "now", "last
week", or "Wed Feb 15 21:02:39 GMT 2023".
-cat cat the files on the command line to stdout.
-f, -force
if file already exists then overwrite.
-pf FILE
output a pseudo file equivalent of the input Squashfs filesystem, use - for stdout.
Filesystem information and listing options:
-s, -stat
display filesystem superblock information.
-max LEVELS, -max-depth LEVELS
descend at most LEVELS of directories when listing.
-i, -info
print files as they are extracted.
-li, -linfo
print files as they are extracted with file attributes (like ls -l output).
-l, -ls
list filesystem, but do not extract files.
-ll, -lls
list filesystem with file attributes (like ls -l output), but do not extract files.
-lln, -llnumeric
same as -lls but with numeric uids and gids.
-lc list filesystem concisely, displaying only files and empty directories. Do not
extract files.
-llc list filesystem concisely with file attributes, displaying only files and empty
directories. Do not extract files.
-full, -full-precision
use full precision when displaying times including seconds. Use with -linfo, -lls,
-lln and -llc.
-UTC use UTC rather than local time zone when displaying time.
-mkfs-time
display filesystem superblock time, which is an unsigned 32-bit int representing
the time in seconds since the epoch (1970-01-01).
Filesystem extended attribute (xattrs) options:
-no, -no-xattrs
do not extract xattrs in file system.
-x, -xattrs
extract xattrs in file system (default).
-xattrs-exclude REGEX
exclude any xattr names matching REGEX. REGEX is a POSIX regular expression, e.g.
-xattrs-exclude '^user.' excludes xattrs from the user namespace.
-xattrs-include REGEX
include any xattr names matching REGEX. REGEX is a POSIX regular expression, e.g.
-xattrs-include '^user.' includes xattrs from the user namespace.
Unsquashfs runtime options:
-v, -version
print version, licence and copyright information.
-p NUMBER, -processors NUMBER
use NUMBER processors. By default will use the number of processors available.
-q, -quiet
no verbose output.
-n, -no-progress
do not display the progress bar.
-percentage
display a percentage rather than the full progress bar. Can be used with dialog
--gauge etc.
-ig, -ignore-errors
treat errors writing files to output as non-fatal.
-st, -strict-errors
treat all errors as fatal.
-no-exit, -no-exit-code
do not set exit code (to nonzero) on non-fatal errors.
-da SIZE, -data-queue SIZE
set data queue to SIZE Mbytes. Default 256 Mbytes.
-fr SIZE, -frag-queue SIZE
set fragment queue to SIZE Mbytes. Default 256 Mbytes.
Miscellaneous options:
-h, -help
output this options text to stdout.
-o BYTES, -offset BYTES
skip BYTES at start of FILESYSTEM. Optionally a suffix of K, M or G can be given
to specify Kbytes, Mbytes or Gbytes respectively (default 0 bytes).
-fstime
synonym for -mkfs-time.
-e, -ef EXTRACT FILE
synonym for -extract-file.
-exc, -excf EXCLUDE FILE
synonym for -exclude-file.
-L synonym for -follow-symlinks.
-pseudo-file FILE
alternative name for -pf.
DECOMPRESSORS AVAILABLE
gzip, lzo, lz4, xz, zstd, lzma
EXIT STATUS
0 The filesystem listed or extracted OK.
1 FATAL errors occurred, e.g. filesystem corruption, I/O errors. Unsquashfs did not
continue and aborted.
2 Non-fatal errors occurred, e.g. no support for XATTRs, Symbolic links in output
filesystem or couldn't write permissions to output filesystem. Unsquashfs continued
and did not abort.
See -ignore-errors, -strict-errors and -no-exit-code options for how they affect the exit
status.
EXAMPLES
unsquashfs IMAGE.SQFS
Extract IMAGE.SQFS to "squashfs-root" in the current working directory.
unsquashfs -d output IMAGE.SQFS
Extract IMAGE.SQFS to "output" in the current working directory.
unsquashfs -d . IMAGE.SQFS
Extract IMAGE.SQFS to current working directory.
unsquashfs -linfo IMAGE.SQFS
Output a listing of IMAGE.SQFS with file attributes to stdout, while extracting the
filesystem to "squashfs-root".
unsquashfs -lls IMAGE.SQFS
Output a listing of IMAGE.SQFS with file attributes to stdout, but do not extract
the filesystem. The listing will be prefixed with "squashfs-root".
unsquashfs -d "" -lls IMAGE.SQFS
Output a listing of IMAGE.SQFS with file attributes to stdout, but do not extract
the filesystem. The listing will not be prefixed with "squashfs-root".
unsquashfs IMAGE.SQFS fs/squashfs
Extract only the "fs/squashfs" directory.
unsquashfs IMAGE.SQFS "[Tt]est/example*"
Extract all files beginning with "example" inside top level directories called
"Test" or "test".
unsquashfs -excludes IMAGE.SQFS "test/*data*.gz"
This will extract everything except for files that match *data*.gz in the test
directory. The -excludes option tells Unsquashfs to exclude the files on the
command line rather than extract them.
unsquashfs -excludes IMAGE.SQFS "... *.gz"
This will extract everything except for files that match *.gz anywhere in the
image. The "..." means this is a non-anchored exclude which matches anywhere.
unsquashfs -ex "test/*data*.gz" ; IMAGE.SQFS test
This uses both extract and exclude options, to tell Unsquashfs to only extract the
"test" directory, and to exclude any files within it that match *data*.gz.
unsquashfs -ex "... *.gz" IMAGE.SQFS test
This uses both extract and exclude options, to tell Unsquashfs to only extract the
"test" directory, and to exclude files which match "*.gz" anywhere within "test"
directory or sub-directories.
unsquashfs -dest output -max-depth 2 IMAGE.SQFS
Extract only the top two levels of IMAGE.SQFS to "output" directory.
unsquashfs -max-depth 2 IMAGE.SQFS "test/*.gz"
Only extract the gzipped files in the test directory.
unsquashfs -llc -max-depth 2 IMAGE.SQFS "test/*.gz"
Output a listing of the gzipped files in the test directory to stdout, but do not
extract them.
unsquashfs -no-xattrs IMAGE.SQFS
Do not extract any extended attributes. Any extended attributes in the filesystem
will be ignored.
unsquashfs -xattrs-include "^user." IMAGE.SQFS
Filter the extended attributes and only extract extended attributes in the user
namespace from the Squashfs filesystem.
unsquashfs -xattrs-exclude "^user." IMAGE.SQFS
Filter the extended attributes and do not extract any extended attributes in the
user namespace from the Squashfs filesystem.
Note: when passing wildcarded names to Unsquashfs, they should be quoted (as in the above
examples), to ensure that they are not processed by the shell.
AUTHOR
Written by Phillip Lougher <phillip@squashfs.org.uk>
COPYRIGHT
Copyright © 2023 Phillip Lougher <phillip@squashfs.org.uk>
This program is free software; you can redistribute it and/or modify it under the terms of
the GNU General Public License as published by the Free Software Foundation; either
version 2, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
SEE ALSO
mksquashfs(1), sqfstar(1), sqfscat(1)
The README for the Squashfs-tools 4.6.1 release, describing the new features can be read
here https://github.com/plougher/squashfs-tools/blob/master/README-4.6.1
The Squashfs-tools USAGE guide can be read here
https://github.com/plougher/squashfs-tools/blob/master/USAGE-4.6