Ubuntu Manpage: unsquashfs - tool to uncompress, extract and list squashfs filesystems

Provided by: squashfs-tools_4.6.1-1build1_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.