Linux Manpages Online - man.cx manual pages

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 )]

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 [AT] squashfs.uk>

COPYRIGHT

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.

Manpages