mksquashfs Man page

Resume Wikipedia de SquashFS

SquashFS est un système de fichiers compressé en lecture seule sous Linux.
Il peut être utilisé à partir de flash, CD-ROM ou disque dur pour des systèmes de fichiers disponible en lecture seulement.
Il est notamment utilisé pour de nombreux Live CD et en informatique embarquée, en remplacement de Cramfs.

MKSQUASHFS(1) create and append squashfs filesystems MKSQUASHFS(1)


mksquashfs – tool to create and append to squashfs filesystems




Squashfs is a highly compressed read-only filesystem for Linux. It uses
zlib compression to compress both files, inodes and directories. Inodes
in the system are very small and all blocks are packed to minimize data
overhead. Block sizes greater than 4K are supported up to a maximum of

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.


Filesystem build options
select COMPRESSION compression. Compressors available: gzip
(default), lzo, xz.

set data block to BLOCK_SIZE. Default 131072 bytes.

don’t make the filesystem exportable via NFS.

don’t detect sparse files.

don’t store extended attributes.

store extended attributes (default).

do not compress inode table.

do not compress data blocks.

do not compress fragment blocks.

do not compress extended attributes.

do not use fragments.

use fragment blocks for files larger than block size.

do not perform duplicate checking.

make all files owned by root.

-force-uid uid
set all file uids to uid.

-force-gid gid
set all file gids to gid.

do not pad filesystem to a multiple of 4K.

if one source directory is specified, create a root directory con‐
taining that directory, rather than the contents of the directory.

Filesystem filter options
Add pseudo file definition.

Add list of pseudo file definitions.

sort files according to priorities in SORT_FILE. One file or dir
with priority per line. Priority -32768 to 32767, default priority

list of exclude dirs/files. One per line.

Allow extended shell wildcards (globbing) to be used in exclude

Allow POSIX regular expressions to be used in exclude dirs/files.

Filesystem append options
do not append to existing filesystem.



when appending source files/directories, make the original root
become a subdirectory in the new root called NAME, rather than
adding the new source items to the original root.

Mksquashfs runtime options:
print version, licence and copyright message.



recover filesystem data using recovery file NAME.

don’t generate a recovery file.

print files written to filesystem.

don’t display the progress bar.

-processors NUMBER
Use NUMBER processors. By default will use number of processors

-read-queue SIZE
Set input queue to SIZE Mbytes. Default 64 Mbytes.

-write-queue SIZE
Set output queue to SIZE Mbytes. Default 512 Mbytes.

-fragment-queue SIZE
Set fragment queue to SIZE Mbytes. Default 64 Mbytes.

Miscellaneous options
alternative name for -all-root.

alternative name for -noI.

alternative name for -noD.

alternative name for -noF.

alternative name for -noX.

Compressors available and compressor specific options
gzip (no options) (default)

lzo (no options)


-Xbcj filter1,filter2,…,filterN
Compress using filter1,filter2,…,filterN in turn (in addition to
no filter), and choose the best compression. Available filters:
x86, arm, armthumb, powerpc, sparc, ia64.

-Xdict-size DICT_SIZE
Use DICT_SIZE as the XZ dictionary size. The dictionary size can be
specified as a percentage of the block size, or as an absolute
value. The dictionary size must be less than or equal to the block
size and 8192 bytes or larger. It must also be storable in the xz
header as either 2^n or as 2^n+2^(n+1). Example dict-sizes are 75%,
50%, 37.5%, 25%, or 32K, 16K, 8K etc.



More information about mksquashfs and the squashfs filesystem can be
found at .


squashfs was written by Phillip Lougher .

This manual page was written by Daniel Baumann .

4.2 2012-06-30 MKSQUASHFS(1)