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sqfscat - Man Page

tool to cat files from a squashfs filesystem to stdout

Examples (TL;DR)


sqfscat [Options] FILESYSTEM [list of files to cat to stdout]


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.


-v,  -version

print version, licence and copyright information.

-p NUMBER, -processors NUMBER

use NUMBER processors.  By default will use the number of processors available.

-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.

-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 filenames.

-r,  -regex

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

-h,  -help

output options text to stdout.

Decompressors Available

gzip, lzo, lz4, xz, zstd, lzma

Exit Status


The file or files were output to stdout OK.


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


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.


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.


Written by Phillip Lougher <phillip@squashfs.org.uk>

See Also

mksquashfs(1), unsquashfs(1), sqfstar(1)

The README for the Squashfs-tools 4.6.1 release, describing the new features can be read here https://github.com/plougher/squashfs-tools/blob/master/README-4.6.1

The Squashfs-tools USAGE guide can be read here https://github.com/plougher/squashfs-tools/blob/master/USAGE-4.6

Referenced By

mksquashfs(1), sqfstar(1), unsquashfs(1).

January 2024 sqfscat version 4.6.1