Provided by: squashfs-tools_4.6.1-1build1_amd64 bug

NAME

       sqfstar - tool to create a squashfs filesystem from a tar archive

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]

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.

OPTIONS

   Filesystem compression options:
       -b 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.

       -comp COMP
              select COMP compression. Compressors available: gzip (default), lzo, lz4, xz, zstd,
              lzma.

       -noI   do not compress inode table.

       -noId  do not compress the uid/gid table (implied by -noI).

       -noD   do not compress data blocks.

       -noF   do not compress fragment blocks.

       -noX   do not compress extended attributes.

       -no-compression
              do not compress any of the data or metadata.  This is equivalent to specifying -noI
              -noD -noF and -noX.

   Filesystem build options:
       -reproducible
              build filesystems that are reproducible (default).

       -not-reproducible
              build filesystems that are not reproducible.

       -mkfs-time TIME
              set  filesystem  creation  timestamp  to  TIME.  TIME can be an unsigned 32-bit int
              indicating seconds since the epoch (1970-01-01) or a string value which  is  passed
              to  the "date" command to parse. Any string value which the date command recognises
              can be used such as "now", "last week", or "Wed Feb 15 21:02:39 GMT 2023".

       -all-time TIME
              set all file timestamps to TIME. TIME can be  an  unsigned  32-bit  int  indicating
              seconds  since  the  epoch  (1970-01-01)  or  a string value which is passed to the
              "date" command to parse. Any string value which the date command recognises can  be
              used such as "now", "last week", or "Wed Feb 15 21:02:39 GMT 2023".

       -root-time TIME
              set  root  directory  time  to  TIME. TIME can be an unsigned 32-bit int indicating
              seconds since the epoch (1970-01-01) or a string  value  which  is  passed  to  the
              "date"  command to parse. Any string value which the date command recognises can be
              used such as "now", "last week", or "Wed Feb 15 21:02:39 GMT 2023".

       -root-mode MODE
              set root directory permissions to octal MODE.

       -root-uid VALUE
              set root directory owner to specified VALUE, VALUE can be either an integer uid  or
              user name.

       -root-gid VALUE
              set  root directory group to specified VALUE, VALUE can be either an integer gid or
              group name.

       -all-root
              make all files owned by root.

       -force-uid VALUE
              set all file uids to specified VALUE, VALUE can be either an integer  uid  or  user
              name.

       -force-gid VALUE
              set  all  file gids to specified VALUE, VALUE can be either an integer gid or group
              name.

       -default-mode MODE
              tar files often do not store permissions for intermediate directories.  This option
              sets  the  default directory permissions to octal MODE, rather than 0755. This also
              sets the root inode mode.

       -default-uid UID
              tar files often do not store uids for intermediate directories.  This  option  sets
              the default directory owner to UID, rather than the user running Sqfstar. This also
              sets the root inode uid.

       -default-gid GID
              tar files often do not store gids for intermediate directories.  This  option  sets
              the  default  directory  group  to  GID,  rather than the group of the user running
              Sqfstar.  This also sets the root inode gid.

       -pseudo-override
              make pseudo file uids  and  gids  override  -all-root,  -force-uid  and  -force-gid
              options.

       -exports
              make the filesystem exportable via NFS.

       -no-sparse
              do not detect sparse files.

       -no-fragments
              do not use fragments.

       -no-tailends
              do not pack tail ends into fragments.

       -no-duplicates
              do not perform duplicate checking.

       -no-hardlinks
              do not hardlink files, instead store duplicates.

   Filesystem filter options:
       -p PSEUDO-DEFINITION
              add pseudo file definition.  The definition should be quoted.

       -pf PSEUDO-FILE
              add  list  of  pseudo  file  definitions.   Pseudo file definitions in pseudo-files
              should not be quoted.

       -ef EXCLUDE_FILE
              list of exclude dirs/files.  One per line.

       -regex allow POSIX regular expressions to be used in exclude dirs/files.

       -ignore-zeros
              allow tar files to be concatenated together and fed to Sqfstar.  Normally a tarfile
              has  two  consecutive 512 byte blocks filled with zeros which means EOF and Sqfstar
              will stop reading after the first tar file on encountering them. This option  makes
              Sqfstar ignore the zero filled blocks.

   Filesystem extended attribute (xattrs) options:
       -no-xattrs
              do not store extended attributes.

       -xattrs
              store extended attributes (default).

       -xattrs-exclude REGEX
              exclude  any xattr names matching REGEX.  REGEX is a POSIX regular expression, e.g.
              -xattrs-exclude '^user.' excludes xattrs from the user namespace.

       -xattrs-include REGEX
              include any xattr names matching REGEX.  REGEX is a POSIX regular expression,  e.g.
              -xattrs-include '^user.' includes xattrs from the user namespace.

       -xattrs-add NAME=VAL
              add the xattr NAME with VAL to files.  If an user xattr it will be added to regular
              files and directories (see man 7 xattr).  Otherwise it will be added to all  files.
              VAL by default will be treated as binary (i.e. an uninterpreted byte sequence), but
              it can be prefixed with 0s, where it will be treated as base64 encoded, or prefixed
              with 0x, where val will be treated as hexidecimal.  Additionally it can be prefixed
              with 0t where this encoding is similar to binary encoding, except  backslashes  are
              specially treated, and a backslash followed by 3 octal digits can be used to encode
              any ASCII character, which obviously can be used  to  encode  control  codes.   The
              option can be repeated multiple times to add multiple xattrs.

   Sqfstar runtime options:
       -version
              print version, licence and copyright message.

       -force force Sqfstar to write to block device or file.

       -exit-on-error
              treat normally ignored errors as fatal.

       -quiet no verbose output.

       -info  print files written to filesystem.

       -no-progress
              do not display the progress bar.

       -progress
              display progress bar when using the -info option.

       -percentage
              display  a  percentage  rather  than the full progress bar. Can be used with dialog
              --gauge etc.

       -throttle PERCENTAGE
              throttle the I/O input rate by the given percentage. This can be used to reduce the
              I/O and CPU consumption of Sqfstar.

       -limit PERCENTAGE
              limit  the  I/O  input rate to the given percentage. This can be used to reduce the
              I/O and CPU consumption of Sqfstar (alternative to -throttle).

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

       -mem SIZE
              use SIZE physical memory for caches.  Use K, M or G to specify  Kbytes,  Mbytes  or
              Gbytes respectively.

       -mem-percent PERCENT
              use PERCENT physical memory for caches.  Default 25%.

       -mem-default
              print default memory usage in Mbytes.

   Expert options (these may make the filesystem unmountable):
       -nopad do not pad filesystem to a multiple of 4K.

       -offset 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.

       -o OFFSET
              synonym for -offset.

   Miscellaneous options:
       -fstime TIME
              alternative name for mkfs-time.

       -root-owned
              alternative name for -all-root.

       -noInodeCompression
              alternative name for -noI.

       -noIdTableCompression
              alternative name for -noId.

       -noDataCompression
              alternative name for -noD.

       -noFragmentCompression
              alternative name for -noF.

       -noXattrCompression
              alternative name for -noX.

       -help  output this options text to stdout.

       -h     output this options text to stdout.

       -Xhelp print compressor options for selected compressor.

PSEUDO FILE DEFINITION FORMAT

       -p "filename d mode uid gid"
              create a directory.

       -p "filename m mode uid gid"
              modify filename.

       -p "filename b mode uid gid major minor"
              create a block device.

       -p "filename c mode uid gid major minor"
              create a character device.

       -p "filename f mode uid gid command"
              create file from stdout of command.

       -p "filename s mode uid gid symlink"
              create a symbolic link.

       -p "filename i mode uid gid [s|f]"
              create a socket (s) or FIFO (f).

       -p "filename x name=val"
              create an extended attribute.

       -p "filename l linkname"
              create a hard-link to linkname.

       -p "filename L pseudo_filename"
              same, but link to pseudo file.

       -p "filename D time mode uid gid"
              create a directory with timestamp time.

       -p "filename M time mode uid gid"
              modify a file with timestamp time.

       -p "filename B time mode uid gid major minor"
              create block device with timestamp time.

       -p "filename C time mode uid gid major minor"
              create char device with timestamp time.

       -p "filename F time mode uid gid command"
              create file with timestamp time.

       -p "filename S time mode uid gid symlink"
              create symlink with timestamp time.

       -p "filename I time mode uid gid [s|f]"
              create socket/fifo with timestamp time.

COMPRESSORS AVAILABLE AND COMPRESSOR SPECIFIC OPTIONS

   gzip (default):
       -Xcompression-level COMPRESSION-LEVEL
              COMPRESSION-LEVEL should be 1 .. 9 (default 9).

       -Xwindow-size WINDOW-SIZE
              WINDOW-SIZE should be 8 .. 15 (default 15).

       -Xstrategy 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.

   lzo:
       -Xalgorithm ALGORITHM
              Where ALGORITHM is one of: lzo1x_1, lzo1x_1_11, lzo1x_1_12,  lzo1x_1_15,  lzo1x_999
              (default).

       -Xcompression-level COMPRESSION-LEVEL
              COMPRESSION-LEVEL should be 1 .. 9 (default 8) Only applies to lzo1x_999 algorithm.

   lz4:
       -Xhc   Compress using LZ4 High Compression.

   xz:
       -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.

   zstd:
       -Xcompression-level COMPRESSION-LEVEL
              COMPRESSION-LEVEL should be 1 .. 22 (default 15).

   lzma:
              (no options) (deprecated - no kernel support)

ENVIRONMENT

       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.

EXAMPLES

       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.

       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.

       sqfstar -b 1M -comp zstd IMAGE.SQFS < archive.tar
              Use a block size of 1 Mbyte and Zstandard compression to create the filesystem.

       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.

       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).

       sqfstar IMAGE.SQFS file1 file2 < archive.tar
              Exclude file1 and file2 from the tar file when creating filesystem.

       sqfstar IMAGE.SQFS "*.gz" < archive.tar
              Exclude any files in the top level directory which  matches  the  wildcard  pattern
              "*.gz".

       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.

       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.

   Using pseudo file definitions
       sqfstar -p "build_dir d 0644 0 0" IMAGE.SQFS < archive.tar
              Create a directory called "build_dir" in the output filesystem.

       sqfstar -p "version.txt l /tmp/build/version" IMAGE.SQFS < archive.tar
              Create a reference called "version.txt" to a file not in  the  tar  archive,  which
              acts as if that file was in the tar archive.

       sqfstar -p "date.txt f 0644 0 0 date" IMAGE.SQFS < archive.tar
              Create  a  file  called "date.txt" which holds the output (stdout) from running the
              "date" command.

       sqfstar -p "\"hello world\" f 0644 0 0 date" IMAGE.SQFS < archive.tar
              As above, but, showing that filenames can have spaces, if  they  are  quoted.   The
              quotes need to be blackslashed to protect them from the shell.

       sqfstar -p "input f 0644 root root dd if=/dev/sda1 bs=1024" IMAGE.SQFS < archive.tar
              Create  a  file  containing the contents of partition /dev/sda1".  The above allows
              input from  these  special  files  to  be  captured  and  placed  in  the  Squashfs
              filesystem.

       Note:  pseudo file definitions should be quoted (as in the above examples), to ensure that
       they are passed to Mksquashfs as a single argument,  and  to  ensure  that  they  are  not
       processed by the shell.

AUTHOR

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

COPYRIGHT

       Copyright © 2023 Phillip Lougher <phillip@squashfs.org.uk>

       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.

       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.

SEE ALSO

       mksquashfs(1), unsquashfs(1), sqfscat(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