UNSQUASHFS(1) User Commands UNSQUASHFS(1) NAME unsquashfs - tool to uncompress, extract and list squashfs filesystems SYNOPSIS unsquashfs [OPTIONS] FILESYSTEM [files to extract or exclude (with -ex- cludes) 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 -fol- low-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 directo- ries. 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 (default). -x, -xattrs extract xattrs in file system (unsupported). -xattrs-exclude REGEX exclude any xattr names matching REGEX. REGEX is a POSIX regular ex- pression, 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 ex- pression, 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 (de- fault 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. Un- squashfs 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 direc- tory. 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 directo- ries 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 ex- clude 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 any- where 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 std- out, 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 at- tributes 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 (C) 2023 Phillip Lougher <phillip@squashfs.org.uk> This program is free software; you can redistribute it and/or modify it un- der the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later ver- sion. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT- NESS 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 fea- tures can be read here https://github.com/plougher/squashfs-tools/blob/mas- ter/README-4.6.1 The Squashfs-tools USAGE guide can be read here https://github.com/plougher/squashfs-tools/blob/master/USAGE-4.6 unsquashfs version 4.6.1 August 2026 UNSQUASHFS(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DECOMPRESSORS AVAILABLE | EXIT STATUS | EXAMPLES | AUTHOR | COPYRIGHT | SEE ALSO
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