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 64K.
.PP
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.
.SHOPTIONS
.SSFilesystembuildoptions
.IP"\-comp \fICOMPRESSION\fR"4
select \fICOMPRESSION\fR compression. Compressors available: gzip (default), lzma (no kernel support), lzo, lz4 and xz.
.IP"\-b \fIBLOCK_SIZE\fR"
set data block to \fIBLOCK_SIZE\fR. Default 131072 bytes. Optionally K or M can be used as a suffix to specify kilobytes or megabytes, respectively.
.IP"\-no\-exports"4
don't make the filesystem exportable via NFS.
.IP"\-no\-sparse"4
don't detect sparse files.
.IP"\-no\-xattrs"4
don't store extended attributes.
.IP"\-xattrs"4
store extended attributes (default).
.IP"\-noI"4
do not compress inode table.
.IP"\-noD"4
do not compress data blocks.
.IP"\-noF"4
do not compress fragment blocks.
.IP"\-noX"4
do not compress extended attributes.
.IP"\-no\-fragments"4
do not use fragments.
.IP"\-always\-use\-fragments"4
use fragment blocks for files larger than block size.
.IP"\-no\-duplicates"4
do not perform duplicate checking.
.IP"\-all\-root"4
make all files owned by root.
.IP"\-force\-uid uid"4
set all file uids to uid.
.IP"\-force\-gid gid"4
set all file gids to gid.
.IP"\-nopad"4
do not pad filesystem to a multiple of 4K.
.IP"\-keep\-as\-directory"4
if one source directory is specified, create a root directory containing that directory, rather than the contents of the directory.
.IP"\-all\-time time"
32 bit integer indicating seconds since the epoch (1970\-01\-01) used for the timestamp for all files. The SOURCE_DATE_EPOCH environment variable can also be used.
.SSFilesystemfilteroptions
.IP"\-p \fIPSEUDO_DEFINITION\fR"4
Add pseudo file definition.
.IP"\-pf \fIPSEUDO_FILE\fR"4
Add list of pseudo file definitions.
.IP"\-sort \fISORT_FILE\fR"4
sort files according to priorities in \fISORT_FILE\fR. One file or dir with priority per line. Priority \-32768 to 32767, default priority 0.
.IP"\-ef \fIEXCLUDE_FILE\fR"4
list of exclude dirs/files. One per line.
.IP"\-wildcards"4
Allow extended shell wildcards (globbing) to be used in exclude dirs/files
.IP"\-regex"4
Allow POSIX regular expressions to be used in exclude dirs/files.
.SSFilesystemappendoptions
.IP"\-noappend"4
do not append to existing filesystem.
.IP"\-root\-becomes \fINAME\fR"4
when appending source files/directories, make the original root become a subdirectory in the new root called \fINAME\fR, rather than adding the new source items to the original root.
.SSMksquashfsruntimeoptions:
.IP"\-version"4
print version, licence and copyright message.
.IP"\-exit\-on\-error"4
treat normally ignored errors as fatal.
.IP"\-recover \fINAME\fR"4
recover filesystem data using recovery file \fINAME\fR.
.IP"\-no\-recovery"4
don't generate a recovery file.
.IP"\-info"4
print files written to filesystem.
.IP"\-no\-progress"4
don't display the progress bar.
.IP"\-progress"4
display progress bar when using the \-info option.
.IP"\-processors \fINUMBER\fR"4
Use \fINUMBER\fR processors. By default will use number of processors available.
.IP"\-mem \fISIZE\fR"4
Use \fISIZE\fR physical memory. Optionally K or M can be used as a suffix for kilobytes or megabytes, respectively. Default 25% of memory.
.IP"\-read\-queue \fISIZE\fR"4
Deprecated. Use \-mem instead.
.IP"\-write\-queue \fISIZE\fR"4
Deprecated. Use \-mem instead.
.IP"\-fragment\-queue \fISIZE\fR"4
Deprecated. Use \-mem instead.
.IP"\-mkfs\-time time"
32 bit integer indicating seconds since the epoch (1970\-01\-01). The SOURCE_DATE_EPOCH environment variable can also be used.
.IP"-not\-reproducible"
This option tells Mksquashfs that the files do not have to be strictly ordered.
Compress using strategy1,strategy2,...,strategyN in turn and choose the best compression. Available strategies: default, filtered, huffman_only, run_length_encoded and fixed
.IP"lzmz (no options) (no kernel support)"4
.IP"lzo"4
.IP"\-Xalgorithm \fIalgorithm\fR"4
Where \fIalgorithm\fR is one of: lzo1x_1, lzo1x_1_11, lzo1x_1_12, lzo1x_1_15 or lzo1x_999. (default lzo1x_999)
\fIcompression\-level\fR should be 1 .. 9 (default 8)
.IP"lz4"4
.IP"\-Xhc"
Compress using LZ4 High Compression
.IP"xz"4
.IP"\-Xbcj filter1,filter2,...,filterN"4
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.
.IP"\-Xdict\-size \fIDICT_SIZE\fR"4
Use \fIDICT_SIZE\fR 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.
.IP"zstd"4
.IP"\-Xcompression-level <compression-level>"4
<compression-level> should be 1 .. 22 (default 15)
.SHSEEALSO
unsquashfs(1)
.SHHOMEPAGE
More information about mksquashfs and the squashfs filesystem can be found at <\fIhttp://squashfs.sourceforge.net/\fR>.
.SHAUTHOR
squashfs was written by Phillip Lougher <\fIplougher@users.sourceforge.net\fR>.
.PP
This manual page was written by Daniel Baumann <\fIdaniel.baumann@progress\-technologies.net\fR>. With some updates for 4.4 for use with Fedora.
mksquashfs \- tool to uncompress squashfs filesystems
.SHSYNOPSIS
\fBunsquashfs\fR [\fIOPTIONS\fR] \fIFILESYSTEM\fR [\fIdirectories or files to extract\fR]
.SHDESCRIPTION
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 64K.
.PP
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.
.SHOPTIONS
.IP"\-v, \-version"4
print version, licence and copyright information.
.IP"\-d \fIPATHNAME\fR, \-dest \fIPATHNAME\fR"4
unsquash to \fIPATHNAME\fR, default "squashfs\-root".
.IP"\-n, \-no\-progress"4
don't display the progress bar.
.IP"\-no, \-no\-xattrs"4
don't extract xattrs in file system.
.IP"\-x, \-xattrs"4
extract xattrs in file system (default).
.IP"\-u, \-user\-xattrs"4
only extract user xattrs in file system. Enables extracting xattrs.
.IP"\-p \fINUMBER\fR, \-processors \fINUMBER\fR"4
use \fINUMBER\fR processors. By default will use number of processors available.
.IP"\-i, \-info"4
print files as they are unsquashed.
.IP"\-li, \-linfo"4
print files as they are unsquashed with file attributes (like ls \-l output).
.IP"\-l, \-ls"4
list filesystem, but don't unsquash.
.IP"\-ll, \-lls"4
list filesystem with file attributes (like ls \-l output), but don't unsquash.
