0
The filesystem listed or extracted OK.
unsquashfs1
Tool to uncompress, extract and list squashfs filesystems
Usage
unsquashfs [OPTIONS]
FILESYSTEM
[files
to
extract
or
exclude
(with
-excludes)
or
cat
(with
-cat
)]
Overview
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-symlinksand-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 destination directory already exists, descend into it and any sub-directories, and unlink (delete) files if they already exist before extracting to them.
-
-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
-loutput).
-
-l, -ls -
list filesystem, but do not extract files.
-
-ll, -lls -
list filesystem with file attributes (like ls
-loutput), but do not extract files.
-
-lln, -llnumeric -
same as
-llsbut 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,-llnand-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.
-
-mem SIZE -
use SIZE physical memory for caches. Use K, M or G to specify Kbytes, Mbytes or Gbytes respectively. Default 512 Mbytes.
-
-mem-percent PERCENT -
use PERCENT physical memory for caches.
-
-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
--gaugeetc.
-
-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.
Help options:
-
-h, -help -
print help summary information to pager (or stdout if not a terminal).
-
-help-option REGEX -
print the help information for options matching REGEX to pager (or stdout if not a terminal).
-
-help-section SECTION -
print the help information for section SECTION to pager (or stdout if not a terminal). If SECTION does not exactly match a section name, it is treated as a regular expression, and all section names that match are displayed. Use "list" as section name to get a list of sections and their names.
-
-help-all -
print help information for all Unsquashfs options and sections to pager (or stdout if not a terminal).
-
-ho REGEX -
shorthand alternative to
-help-option.
-
-hs SECTION -
shorthand alternative to
-help-section.
-
-ha -
shorthand alternative to
-help-all.
-
-no-pager -
do not use a pager to output help information.
-
-cols WIDTH -
use WIDTH columns to output help information. Useful if output is not to a terminal.
Miscellaneous options:
-
-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.
|
synonym for |
|---|---|
|
synonym for |
-
-L -
synonym for
-follow-symlinks.
-
-pseudo-file FILE -
alternative name for
-pf.
Exit status
-
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.
Decompressors available
gzip, lzo, lz4, xz, zstd, lzma
Environment
-
SQFS_CMDLINE -
If set, this is used as the directory to write the file sqfs_cmdline which contains the command line arguments given to Unsquashfs. Each command line argument is wrapped in quotes to ensure there is no ambiguity when arguments contain spaces. If the file already exists then the command line is appended to the file.
-
PAGER -
If set, this is used as the name of the program used to display the help text. The value can be a simple command or a pathname. The default is /usr/bin/pager.
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.
Releases
10 releases since Debian 5.0 (Lenny); the text changed 7 times.
-L since Debian 12 (Bookworm);
-UTC since Debian 12 (Bookworm);
-all since Debian 13 (Trixie);
-all-time since Debian 13 (Trixie);
-cat since Debian 12 (Bookworm);
-cols since Arch Linux 2026-11-01;
-d since Debian 7 (Wheezy);
-dest since Debian 7 (Wheezy);
-ex since Debian 12 (Bookworm);
-exclude-file since Debian 12 (Bookworm);
-exclude-list since Debian 12 (Bookworm);
-excludes since Debian 12 (Bookworm);
-extract-file since Debian 12 (Bookworm);
-follow since Debian 12 (Bookworm);
-follow-symlinks since Debian 12 (Bookworm);
-force since Debian 7 (Wheezy);
-fstime since Debian 12 (Bookworm);
-full since Debian 13 (Trixie);
-full-precision since Debian 13 (Trixie);
-h since Debian 12 (Bookworm);
-ha since Arch Linux 2026-11-01;
-help since Debian 12 (Bookworm);
-help-all since Arch Linux 2026-11-01;
-help-option since Arch Linux 2026-11-01;
-help-section since Arch Linux 2026-11-01;
-ho since Arch Linux 2026-11-01;
-hs since Arch Linux 2026-11-01;
-ig since Debian 12 (Bookworm);
-ignore-errors since Debian 12 (Bookworm);
-info since Debian 7 (Wheezy);
-lc since Debian 12 (Bookworm);
-linfo since Debian 7 (Wheezy);
-llc since Debian 12 (Bookworm);
-lln since Debian 12 (Bookworm);
-llnumeric since Debian 12 (Bookworm);
-lls since Debian 7 (Wheezy);
-ls since Debian 7 (Wheezy);
-match since Debian 13 (Trixie);
-max since Debian 12 (Bookworm);
-max-depth since Debian 12 (Bookworm);
-mem since Arch Linux 2026-11-01;
-mem-percent since Arch Linux 2026-11-01;
-missing since Debian 12 (Bookworm);
-missing-symlinks since Debian 12 (Bookworm);
-mkfs-time since Debian 12 (Bookworm);
-n since Debian 6.0 (Squeeze);
-no since Debian 7 (Wheezy);
-no-exit since Debian 12 (Bookworm);
-no-exit-code since Debian 12 (Bookworm);
-no-pager since Arch Linux 2026-11-01;
-no-progress since Debian 7 (Wheezy);
-no-wild since Debian 12 (Bookworm);
-no-wildcards since Debian 12 (Bookworm);
-no-xattrs since Debian 7 (Wheezy);
-o since Debian 12 (Bookworm);
-offset since Debian 12 (Bookworm);
-p since Debian 7 (Wheezy);
-percentage since Debian 13 (Trixie);
-pf since Debian 12 (Bookworm);
-processors since Debian 7 (Wheezy);
-pseudo-file since Debian 12 (Bookworm);
-q since Debian 12 (Bookworm);
-quiet since Debian 12 (Bookworm);
-regex since Debian 7 (Wheezy);
-st since Debian 12 (Bookworm);
-stat since Debian 7 (Wheezy);
-strict-errors since Debian 12 (Bookworm);
-version since Debian 7 (Wheezy);
-x since Debian 7 (Wheezy);
-xattrs since Debian 7 (Wheezy);
-xattrs-exclude since Debian 13 (Trixie);
-xattrs-include since Debian 13 (Trixie).
-da until Debian 13 (Trixie);
-data-queue until Debian 13 (Trixie);
-e until Debian 11 (Bullseye);
-ef until Debian 11 (Bullseye);
-fr until Debian 13 (Trixie);
-frag-queue until Debian 13 (Trixie);
-nl until Debian 11 (Bullseye);
-nls until Debian 11 (Bullseye);
-u until Debian 12 (Bookworm);
-user-xattrs until Debian 12 (Bookworm).