NAME

       tar2sqfs - create a SquashFS image from a tar archive

SYNOPSIS

       tar2sqfs [OPTIONS...] <sqfsfile>

DESCRIPTION

       Read an uncompressed tar archive from stdin and turn it into a SquashFS filesystem image.

       The idea is to quickly and painlessly turn a tar ball into a SquashFS filesystem image, so existing tools
       that work with tar can be used for SquashFS.

       Possible options:

       --root-becomes, -r <dir>
              If  set, only pack entries that are underneath the specified directory and the prefix is stripped.
              The meta data for the  directory  itself  is  copied  to  the  root  inode,  i.e.  the  ownership,
              permissions,   extended  attributes  (unless  -no-xattris  set),  and  modification  time  (unless
              --no-keep-time is set).

              If this option is not set, tar2sqfs implicitly treats ./ or absolute paths this way, i.e.  if  the
              archive  contains  an  entry  for ./, it becomes the root node and the prefix is stripped from all
              paths (and similar for absolute paths and /).

       --compressor, -c <name>
              Select the compressor to use.  Run tar2sqfs --help to get a list of all available compressors  and
              the default selection.

       --comp-extra, -X <options>
              A comma separated list of extra options for the selected compressor. Specify help to get a list of
              available options.

       --num-jobs, -j <count>
              If libsquashfs was compiled with a thread pool based, parallel data compressor, this option can be
              used  to  set the number of compressor threads. If not set, the default is the number of available
              CPU cores.

       --queue-backlog, -Q <count>
              Maximum number of data blocks in the thread worker queue before the packer starts waiting for  the
              block  processors  to  catch up. Higher values result in higher memory consumption. Defaults to 10
              times the number of workers.

       --block-size, -b <size>
              Block size to use for SquashFS image.  Defaults to 131072.

       --dev-block-size, -B <size>
              Device block size to padd the image to.  Defaults to 4096.

       --defaults, -d <options>
              A comma separated list of default values for implicitly created directories.  The following values
              can be set:
              ┌───────────────┬────────────────────────────────────────┐
              │ Option        │ Default                                │
              ├───────────────┼────────────────────────────────────────┤
              │ uid=<value>   │ 0                                      │
              ├───────────────┼────────────────────────────────────────┤
              │ gid=<value>   │ 0                                      │
              ├───────────────┼────────────────────────────────────────┤
              │ mode=<value>  │ 0755                                   │
              ├───────────────┼────────────────────────────────────────┤
              │ mtime=<value> │ $SOURCE_DATE_EPOCH if set, 0 otherwise │
              └───────────────┴────────────────────────────────────────┘

       --no-keep-time, -k
              Replace the time stamps from the tar archive with default time stamps for all entries.

              The default behavior if not specified, is to preserve the time stamps  from  the  archive  to  the
              extent  possible (SquashFS has second resolution and 32 bit time stamps; tar can use extensions to
              specify much larger timestamps with arbitrary precision). The root inode and the modification time
              on the SquashFS image itself will always still be set to defaults.

       --no-xattr, -x
              Do not copy extended attributes from archive. Default behaviour is to copy all extended attributes
              and skip the ones that cannot be encoded in SquashFS.

       --no-skip, -s
              Abort if a tar record cannot be read instead of skipping it.

       --exportable, -e
              Generate an export table for NFS support.

       --force, -f
              Overwrite the output file if it exists.

       --quiet, -q
              Do not print out progress reports.

       --help, -h
              Print help text and exit.

       --version, -V
              Print version information and exit.

COMPATIBILITY

       Currently the program can process v7 format, pre-POSIX  ustar,  POSIX  tar  and  GNU  tar  archives.  PAX
       extension headers are also supported.

       The  support  for  GNU  tar  is limited to commonly used subset (i.e. some legacy extensions that GNU tar
       itself no longer generates are not supported; neither are mutli volume archives).

       Hard links are currently not supported and silently converted to symlinks.

       Extended attributes are supported through the SCHILY.xattr PAX extension (favoured by GNU tar  and  star)
       or through the LIBARCHIVE.xattr PAX extension.

       If  any  unsupported  section or extended attribute key is encountered in an archive a warning message is
       written to stderr. If the --no-skip option is set, processing aborts. By default,  unknown  sections  and
       unsupported extended attributes are simply skipped after issuing a warning.

ENVIRONMENT

       If  the  command  line  switch  --defaults is not used or no default mtime is specified, the value of the
       environment variable SOURCE_DATE_EPOCH is used for all file and filesystem timestamps.

       If SOURCE_DATE_EPOCH is not set, not a parsable number or it is out of range, the timestamps  default  to
       0.

       Environment  variables  are only used if no explicit command line switches are set. Explicit command line
       switches are always preferred over the environment variables.

EXAMPLES

       Turn an uncompressed tar archive into a SquashFS image:

              tar2sqfs rootfs.sqfs < rootfs.tar

       Turn a gzip'ed tar archive into a SquashFS image:

              zcat rootfs.tar.gz | tar2sqfs rootfs.sqfs

       Turn an LZMA2 compressed tar archive into a SquashFS image:

              xzcat rootfs.tar.xz | tar2sqfs rootfs.sqfs

SEE ALSO

       gensquashfs(1), rdsquashfs(1), sqfs2tar(1)

AUTHOR

       Written by David Oberhollenzer.

COPYRIGHT

       Copyright   ©   2019   David   Oberhollenzer   License   GPLv3+:   GNU   GPL   version   3    or    later
       <https://gnu.org/licenses/gpl.html>.
       This  is  free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent
       permitted by law.

tar2sqfs                                            June 2019                                        TAR2SQFS(1)