.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.49.1.
.TH SQFSTAR "1" "March 2022" "sqfstar version 4.5.1" "User Commands"
.SH NAME
sqfstar - tool to create a squashfs filesystem from a tar archive
.SH SYNOPSIS
  cat xxx.tar | sqfstar [OPTIONS] FILESYSTEM [exclude files]
  zcat xxx.tgz | sqfstar [OPTIONS] FILESYSTEM [exclude files]
  xzcat xxx.tar.xz | sqfstar [OPTIONS] FILESYSTEM [exclude files]
  zstdcat xxx.tar.zst | sqfstar [OPTIONS] FILESYSTEM [exclude files]
.SH 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.
.SH OPTIONS
.SS "Filesystem build options:"
.TP
\fB\-comp\fR COMP
select COMP compression. Compressors available: gzip (default), lzo, lz4, xz, zstd, lzma.
.TP
\fB\-b\fR BLOCK_SIZE
set data block to BLOCK_SIZE.  Default 128 Kbytes. Optionally a suffix of K or M can be given to specify Kbytes or Mbytes respectively.
.TP
\fB\-reproducible\fR
build filesystems that are reproducible (default).
.TP
\fB\-not\-reproducible\fR
build filesystems that are not reproducible.
.TP
\fB\-mkfs\-time\fR TIME
set filesystem creation timestamp to TIME, which is an unsigned 32\-bit int indicating seconds since the epoch (1970\-01\-01).
.TP
\fB\-fstime\fR TIME
synonym for mkfs\-time.
.TP
\fB\-all\-time\fR TIME
set all file timestamps to TIME, which is an unsigned 32\-bit int indicating seconds since the epoch (1970\-01\-01).
.TP
\fB\-exports\fR
make the filesystem exportable via NFS.
.TP
\fB\-no\-sparse\fR
don't detect sparse files.
.TP
\fB\-no\-xattrs\fR
don't store extended attributes.
.TP
\fB\-xattrs\fR
store extended attributes (default).
.TP
\fB\-noI\fR
do not compress inode table.
.TP
\fB\-noId\fR
do not compress the uid/gid table (implied by \fB\-noI\fR).
.TP
\fB\-noD\fR
do not compress data blocks.
.TP
\fB\-noF\fR
do not compress fragment blocks.
.TP
\fB\-noX\fR
do not compress extended attributes.
.TP
\fB\-no\-fragments\fR
do not use fragments.
.TP
\fB\-no\-tailends\fR
don't pack tail ends into fragments.
.TP
\fB\-no\-duplicates\fR
do not perform duplicate checking.
.TP
\fB\-no\-hardlinks\fR
do not hardlink files, instead store duplicates.
.TP
\fB\-all\-root\fR
make all files owned by root.
.TP
\fB\-root\-time\fR TIME
set root directory time to TIME.
.TP
\fB\-root\-mode\fR MODE
set root directory permissions to octal MODE.
.TP
\fB\-root\-uid\fR UID
set root directory owner to UID.
.TP
\fB\-root\-gid\fR GID
set root directory group to GID.
.TP
\fB\-force\-uid\fR UID
set all file uids to UID.
.TP
\fB\-force\-gid\fR GID
set all file gids to GID.
.SS "Filesystem filter options:"
.TP
\fB\-ef\fR EXCLUDE_FILE
list of exclude dirs/files.  One per line.
.TP
\fB\-regex\fR
Allow POSIX regular expressions to be used in exclude dirs/files.
.SS "Sqfstar runtime options:"
.TP
\fB\-version\fR
print version, licence and copyright message.
.TP
\fB\-force\fR
force Sqfstar to write to block device or file.
.TP
\fB\-exit\-on\-error\fR
treat normally ignored errors as fatal.
.TP
\fB\-quiet\fR
no verbose output.
.TP
\fB\-info\fR
print files written to filesystem.
.TP
\fB\-no\-progress\fR
don't display the progress bar.
.TP
\fB\-progress\fR
display progress bar when using the \fB\-info\fR option.
.TP
\fB\-throttle\fR PERCENTAGE
throttle the I/O input rate by the given percentage. This can be used to reduce the I/O and CPU consumption of Mksquashfs.
.TP
\fB\-limit\fR PERCENTAGE
limit the I/O input rate to the given percentage. This can be used to reduce the I/O and CPU consumption of Mksquashfs (alternative to \fB\-throttle\fR).
.TP
\fB\-processors\fR NUMBER
Use NUMBER processors.  By default will use number of processors available.
.TP
\fB\-mem\fR SIZE
Use SIZE physical memory. Optionally a suffix of K, M or G can be given to specify Kbytes, Mbytes or Gbytes respectively.
.SS "Expert options (these may make the filesystem unmountable):"
.TP
\fB\-nopad\fR
do not pad filesystem to a multiple of 4K.
.TP
\fB\-offset\fR OFFSET
Skip OFFSET bytes at the beginning of FILESYSTEM. Optionally a suffix of K, M or G can be given to specify Kbytes, Mbytes or Gbytes respectively. Default 0 bytes.
.TP
\fB\-o\fR OFFSET
synonym for \fB\-offset\fR.
.SS "Miscellaneous options:"
.TP
\fB\-root\-owned\fR
alternative name for \fB\-all\-root\fR.
.TP
\fB\-noInodeCompression\fR
alternative name for \fB\-noI\fR.
.TP
\fB\-noIdTableCompression\fR
alternative name for \fB\-noId\fR.
.TP
\fB\-noDataCompression\fR
alternative name for \fB\-noD\fR.
.TP
\fB\-noFragmentCompression\fR
alternative name for \fB\-noF\fR.
.TP
\fB\-noXattrCompression\fR
alternative name for \fB\-noX\fR.
.TP
\fB\-help\fR
output this options text to stdout.
.TP
\fB\-h\fR
output this options text to stdout.
.TP
\fB\-Xhelp\fR
print compressor options for selected compressor.
.SH "COMPRESSORS AVAILABLE AND COMPRESSOR SPECIFIC OPTIONS"
.SS "gzip (default):"
.TP
\fB\-Xcompression\-level\fR COMPRESSION\-LEVEL
COMPRESSION\-LEVEL should be 1 .. 9 (default 9).
.TP
\fB\-Xwindow\-size\fR WINDOW\-SIZE
WINDOW\-SIZE should be 8 .. 15 (default 15).
.TP
\fB\-Xstrategy\fR strategy1,strategy2,...,strategyN
Compress using strategy1,strategy2,...,strategyN in turn and choose the best compression. Available strategies: default, filtered, huffman_only, run_length_encoded and fixed.
.SS "lzo:"
.TP
\fB\-Xalgorithm\fR ALGORITHM
Where ALGORITHM is one of: lzo1x_1, lzo1x_1_11, lzo1x_1_12, lzo1x_1_15, lzo1x_999 (default).
.TP
\fB\-Xcompression\-level\fR COMPRESSION\-LEVEL
COMPRESSION\-LEVEL should be 1 .. 9 (default 8) Only applies to lzo1x_999 algorithm.
.SS "lz4:"
.TP
\fB\-Xhc\fR
Compress using LZ4 High Compression.
.SS "xz:"
.TP
\fB\-Xbcj\fR 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.
.TP
\fB\-Xdict\-size\fR 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.
.SS "zstd:"
.TP
\fB\-Xcompression\-level\fR COMPRESSION\-LEVEL
COMPRESSION\-LEVEL should be 1 .. 22 (default 15).
.SS "lzma:"
.IP
(no options) (deprecated \- no kernel support)
.SH ENVIRONMENT
.TP
SOURCE_DATE_EPOCH
If set, this is used as the filesystem creation timestamp.  Also any file timestamps which are after SOURCE_DATE_EPOCH will be clamped to SOURCE_DATE_EPOCH.  See https://reproducible\-builds.org/docs/source\-date\-epoch/ for more information.
.SH EXAMPLES
.TP
sqfstar IMAGE.SQFS < archive.tar
Create a Squashfs filesystem from the uncompressed tar file "archive.tar".
Sqfstar will use the default compressor (normally gzip), and block size of 128
Kbytes.
.TP
zcat archive.tgz | sqfstar IMAGE.SQFS
Create a Squashfs filesystem from the compressed tar file "archive.tgz". Sqfstar
will use the default compressor (normally gzip), and block size of 128 Kbytes.
.TP
sqfstar -b 1M -comp zstd IMAGE.SQFS < archive.tar
Use a block size of 1 Mbyte and Zstandard compression to create the filesystem. 
.TP
sqfstar -root-uid 0 -root-gid 0 IMAGE.SQFS < archive.tar
Tar files do not supply a definition for the root directory, and the default is
to make the directory owned/group owned by the user running Sqfstar.  The above
command sets the ownership/group ownership to root.
.TP
sqfstar -root-mode 0755 IMAGE.SQFS < archive.tar
The default permissions for the root directory is 0777 (rwxrwxrwx).  The above
command sets the permissions to 0755 (rwxr-xr-x).
.TP
sqfstar IMAGE.SQFS file1 file2 < archive.tar
Exclude file1 and file2 from the tar file when creating filesystem.
.TP
sqfstar IMAGE.SQFS "*.gz" < archive.tar
Exclude any files in the top level directory which matches the wildcard pattern
"*.gz".
.TP
sqfstar IMAGE.SQFS "... *.gz" < archive.tar
Exclude any file which matches the wildcard pattern "*.gz" anywhere within the
tar file.  The initial "..." indicates the wildcard pattern is "non-anchored"
and will match anywhere.
.PP
Note: when passing wildcarded names to Sqfstar, they should be quoted (as in
the above examples), to ensure that they are not processed by the shell.
.SH AUTHOR
Written by Phillip Lougher <phillip@squashfs.org.uk>
.SH COPYRIGHT
Copyright \(co 2022 Phillip Lougher <phillip@squashfs.org.uk>
.PP
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.
.PP
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.
.SH "SEE ALSO"
mksquashfs(1), unsquashfs(1), sqfscat(1)
.PP
The README for the Squash\-tools 4.5.1 release, describing the new features can be
read here https://github.com/plougher/squashfs\-tools/blob/master/README\-4.5.1
.PP
The Squashfs\-tools USAGE guide can be read here
https://github.com/plougher/squashfs\-tools/blob/master/USAGE