Manual: sqfscat

SQFSCAT(1)						User Commands						  SQFSCAT(1)

NAME
       sqfscat - tool to cat files from a squashfs filesystem to stdout

SYNOPSIS
       sqfscat [OPTIONS] FILESYSTEM [list of files to cat to stdout]

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	min‐
       imise 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
   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.

       -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).

       -ig, -ignore-errors
	      treat errors writing files to stdout 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.

   Filter options:
       -no-wild, -no-wildcards
	      do not use wildcard matching in filenames.

       -r, -regex
	      treat filenames as POSIX regular expressions rather than use the default shell wildcard expansion (globbing).

   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 dis‐
	      played.  Use "list" as section name to get a list of sections and their names.

       -help-all
	      print help information for all Sqfscat 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.

EXIT STATUS
       0      The file or files were output to stdout OK.

       1      FATAL errors occurred, e.g. filesystem corruption, I/O errors.  Sqfscat did not continue and aborted.

       2      Non-fatal	 errors occurred, e.g. not a regular file, or failed to resolve pathname.  Sqfscat 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 Sqfscat.	 Each command line argument is wrapped in quotes to ensure there is no ambiguity when  argu‐
	      ments 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 com‐
	      mand or a pathname.  The default is /usr/bin/pager.

EXAMPLES
       sqfscat IMAGE.SQFS hello
	      Output the contents of "hello" to stdout.

       sqfscat IMAGE.SQFS hello world
	      Output the contents of "hello" and then "world" to stdout.

       sqfscat IMAGE.SQFS "*.[ch]"
	      Output  the  contents  of	 all the files in the root directory that match the wildcard *.[ch], to stdout, e.g.
	      hello.c, hello.h, world.c, world.h.

       Note: when passing wildcarded names to Sqfscat, they should be quoted (as in the above examples), to ensure that they
       are not processed by the shell.

AUTHOR
       Written by Phillip Lougher 

COPYRIGHT
       Copyright © 2026 Phillip Lougher 

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public Li‐
       cense 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 de‐
       tails.

SEE ALSO
       mksquashfs(1), unsquashfs(1), sqfstar(1)

       The  README  for	 the  Squashfs-tools   4.7.5   release,	  describing   the   new   features   can   be	 read	here
       https://github.com/plougher/squashfs-tools/blob/master/Documentation/4.7.5/README.md

       The   Sqfscat   usage   guide  can  be  read  here  https://github.com/plougher/squashfs-tools/blob/master/Documenta‐
       tion/4.7.5/USAGE-SQFSCAT.md

       The CHANGELOG for Squashfs tools can be read here https://github.com/plougher/squashfs-tools/blob/master/CHANGES.md

sqfscat version 4.7.5					 March 2026						  SQFSCAT(1)