Provided by: squashfs-tools_4.5.1-1_amd64 bug

NAME

       mksquashfs - tool to create and append to squashfs filesystems

SYNOPSIS

       mksquashfs source1 source2 ...  FILESYSTEM [OPTIONS] [-e list of exclude dirs/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 build options:
       -tar   read uncompressed tar file from standard in (stdin).

       -no-strip
              act like tar, and do not strip leading directories from source files.

       -tarstyle
              alternative name for -no-strip.

       -cpiostyle
              act like cpio, and read files from standard in (stdin).

       -cpiostyle0
              like -cpiostyle, but filenames are null terminated.

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

       -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.

       -reproducible
              build filesystems that are reproducible (default).

       -not-reproducible
              build filesystems that are not reproducible.

       -mkfs-time TIME
              set filesystem creation  timestamp  to  TIME,  which  is  an  unsigned  32-bit  int
              indicating seconds since the epoch (1970-01-01).

       -fstime TIME
              synonym for mkfs-time.

       -all-time TIME
              set all file timestamps to TIME, which is an unsigned 32-bit int indicating seconds
              since the epoch (1970-01-01).

       -no-exports
              don't make filesystem exportable via NFS (-tar default).

       -exports
              make filesystem exportable via NFS (default).

       -no-sparse
              don't detect sparse files.

       -no-xattrs
              don't store extended attributes.

       -xattrs
              store extended attributes (default).

       -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-tailends
              don't pack tail ends into fragments (default).

       -tailends
              pack tail ends into fragments.

       -no-fragments
              do not use fragments.

       -always-use-fragments
              use fragment blocks for files larger than block size.

       -no-duplicates
              do not perform duplicate checking.

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

       -all-root
              make all files owned by root.

       -root-time TIME
              set root directory time to TIME.

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

       -root-uid UID
              set root directory owner to UID.

       -root-gid GID
              set root directory group to GID.

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

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

       -keep-as-directory
              if one source directory is specified,  create  a  root  directory  containing  that
              directory, rather than the contents of the directory.

       -action ACTION@EXPRESSION
              evaluate EXPRESSION on every file, and execute ACTION if it returns TRUE.

       -log-action ACTION@EXPRESSION
              as above, but log expression evaluation results and actions performed.

       -true-action ACTION@EXPRESSION
              as above, but only log expressions which return TRUE.

       -false-action ACTION@EXPRESSION
              as above, but only log expressions which return FALSE.

       -action-file FILE
              as action, but read actions from FILE.

       -log-action-file FILE
              as -log-action, but read actions from FILE.

       -true-action-file FILE
              as -true-action, but read actions from FILE.

       -false-action-file FILE
              as -false-action, but read actions from FILE.

   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.

       -sort SORT_FILE
              sort files according to priorities in SORT_FILE.  One file or dir with priority per
              line.  Priority -32768 to 32767, default priority 0.

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

       -wildcards
              Allow extended shell wildcards (globbing) to be used in exclude dirs/files.

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

       -one-file-system
              Do not cross filesystem boundaries when scanning sources.

   Filesystem append options:
       -noappend
              do not append to existing filesystem.

       -root-becomes NAME
              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:
       -version
              print version, licence and copyright message.

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

       -recover NAME
              recover filesystem data using recovery file NAME.

       -no-recovery
              don't generate a recovery file.

       -recovery-path NAME
              use NAME as the directory to store the recovery file.

       -quiet no verbose output.

       -info  print files written to filesystem.

       -no-progress
              don't display the progress bar.

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

       -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 Mksquashfs.

       -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 Mksquashfs (alternative to -throttle).

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

       -mem SIZE
              Use  SIZE physical memory. Optionally a suffix of K, M or G can be given to specify
              Kbytes, Mbytes or Gbytes respectively.

   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:
       -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 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

       mksquashfs DIRECTORY IMAGE.SQFS
              Create a Squashfs filesystem from the contents of DIRECTORY, writing the output  to
              IMAGE.SQSH.   Mksquashfs will use the default compressor (normally gzip), and block
              size of 128 Kbytes.

       mksquashfs DIRECTORY FILE1 FILE2 IMAGE.SQFS
              Create a Squashfs filesystem containing DIRECTORY and FILE1 and FILE2.  If multiple
              sources  are  specified  on  the  command  line they will be combined into a single
              directory.

       mksquashfs DIRECTORY IMAGE.SQFS -b 1M -comp zstd
              Use a block size of 1 Mbyte and Zstandard compression to create the filesystem.

       mksquashfs DIRECTORY IMAGE.SQFS -e file1 file2
              Exclude file1 and file2 from  DIRECTORY  when  creating  filesystem.   No  wildcard
              matching of files.

       mksquashfs DIRECTORY IMAGE.SQFS -wildcards -e "*.gz"
              Exclude anything in DIRECTORY which matches the wildcard pattern "*.gz".

       mksquashfs DIRECTORY IMAGE.SQFS -wildcards -e "... *.gz"
              Exclude files which match the wildcard pattern "*.gz" anywhere within DIRECTORY and
              its sub-directories.  The initial "..." indicates the  wildcard  pattern  is  "non-
              anchored" and will match anywhere.

       Note:  when passing wildcarded names to Mksquashfs, they should be quoted (as in the above
       examples), to ensure that they are not processed by the shell.

   Using pseudo file definitions
       mksquashfs DIRECTORY IMAGE.SQFS -p "build_dir d 0644 0 0"
              Create a directory called "build_dir" in the output filesystem.

       mksquashfs DIRECTORY IMAGE.SQFS -p "version.txt l /tmp/build/version"
              Create a reference called "version.txt" to a file outside DIRECTORY, which acts  as
              if  the  file  "/tmp/build/version" was copied or hard-linked into DIRECTORY before
              calling Mksquashfs.

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

       mksquashfs DIRECTORY IMAGE.SQFS -p "\"hello world\" f 0644 0 0 date"
              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.

       mksquashfs - IMAGE.SQFS -p "input f 0644 root root dd if=/dev/sda1 bs=1024" -p "/ d 0644 0
       0"
              Create  a  file  containing  the  contents  of  partition  /dev/sda1".   Ordinarily
              Mksquashfs given a device, fifo, or named  socket  will  place  that  special  file
              within  the Squashfs filesystem, the above allows input from these special files to
              be captured and placed in the  Squashfs  filesystem.    Note  there  are  no  other
              sources  than the pseudo file, and so the command line source is "-".  If there are
              no other sources than pseudo files, the root (/) directory must be defined too,  as
              seen in this example.

       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.

   Using Actions to not compress, change attributes etc.
       mksquashfs  DIRECTORY  IMAGE.SQSH -action "uncompressed @ (name(*.jpg) || name(*.mpg) ) ||
       (name(*.img) && filesize(+1G))"
              Specify that any files matching the wildcards "*.jpg" and  "*.mpg"  should  not  be
              compressed.   Additionally,  it  also  specifies  any  files  matching the wildcard
              "*.img" and are larger than 1 Gigabyte should be uncompressed too.  This shows test
              operators can be combined with logical expressions.

       mksquashfs DIRECTORY IMAGE.SQSH -action "chmod(o+r)@! perm(o+r)"
              If any files within DIRECTORY are not readable by "others", then make them readable
              by others in the Squashfs filesystem.

       mksquashfs DIRECTORY IMAGE.SQSH -action "uid(phillip)@! perm(o+r)"
              As previous, match on any files which are not readable by "others",  but,  in  this
              case change the owner of the file to "phillip" in the Squashfs filesystem.

       mksquashfs DIRECTORY IMAGE.SQSH -action "prune @ type(l) && ! exists"
              Delete  any  symbolic link within DIRECTORY which points outside of DIRECTORY, i.e.
              will be unresolvable in the Squashfs filesystem.

       mksquashfs DIRECTORY IMAGE.SQSH -action "exclude @ depth(3)"
              Create a Squashfs filesystem containing  the  two  top  most  levels  (contents  of
              DIRECTORY and immediate sub-directories), and exclude anything at level 3 or below.

       Note:  actions 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 © 2022 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

       unsquashfs(1), sqfstar(1), sqfscat(1)

       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

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

       The  ACTIONS-README  file  describing  how to use the new actions feature can be read here
       https://github.com/plougher/squashfs-tools/blob/master/ACTIONS-README