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 con-
strained block device/memory systems (e.g. embedded systems) where low
overhead is needed.
OPTIONS
-v, -version
print version, licence and copyright information.
-cat cat the files on the command line to stdout.
-d PATHNAME, -dest PATHNAME
extract to PATHNAME, default "squashfs-root".
-max LEVELS, -max-depth LEVELS
descend at most LEVELS of directories when extracting or list-
ing.
-excludes
treat files on command line as exclude files.
-ex, -exclude-list
list of files to be excluded, terminated with ; e.g. file1 file2
;.
-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.
-q, -quiet
no verbose output.
-n, -no-progress
don't display the progress bar.
-no, -no-xattrs
don't extract xattrs in file system.
-x, -xattrs
extract xattrs in file system (default).
-u, -user-xattrs
only extract user xattrs in file system. Enables extracting xat-
trs.
-p NUMBER, -processors NUMBER
use NUMBER processors. By default will use the number of pro-
cessors available.
-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 don't extract files.
-ll, -lls
list filesystem with file attributes (like ls -l output), but
don't extract files.
-lln, -llnumeric
same as -lls but with numeric uids and gids.
-lc list filesystem concisely, displaying only files and empty di-
rectories. Don't extract files.
-llc list filesystem concisely with file attributes, displaying only
files and empty directories. Don't extract files.
-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 respec-
tively (default 0 bytes).
-f, -force
if file already exists then overwrite.
-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
don't set exit code (to nonzero) on non-fatal errors.
-s, -stat
display filesystem superblock information.
-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).
-fstime
synonym for -mkfs-time.
-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.
-pf FILE
output a pseudo file equivalent of the input Squashfs filesys-
tem.
-pseudo-file FILE
alternative name for -pf.
-e, -ef EXTRACT FILE
synonym for -extract-file.
-exc, -excf EXCLUDE FILE
synonym for -exclude-file.
-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.
-no-wild, -no-wildcards
do not use wildcard matching in extract names.
-r, -regex
treat extract names as POSIX regular expressions rather than use
the default shell wildcard expansion (globbing).
-L synonym for -follow-symlinks.
-h, -help
output this options text to stdout.
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 out-
put 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 di-
rectory.
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.
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 di-
rectories 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 Un-
squashfs to exclude the files on the command line rather than
extract them.
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 -dest output -max-depth 2 IMAGE.SQFS
Extract only the top two levels of IMAGE.SQFS to "output" direc-
tory.
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.
Note: when passing wildcarded names to Unsquashfs, they should be
quoted (as in the above examples), to ensure that they are not pro-
cessed by the shell.
AUTHOR
Written by Phillip Lougher <phillip@squashfs.org.uk>
COPYRIGHT
Copyright © 2022 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 MER-
CHANTABILITY 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 Squash-tools 4.5.1 release, describing the new fea-
tures can be read here
https://github.com/plougher/squashfs-tools/blob/master/README-4.5.1
The Squashfs-tools USAGE guide can be read here
https://github.com/plougher/squashfs-tools/blob/master/USAGE
unsquashfs version 4.5.1 March 2022 UNSQUASHFS(1)
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