NAME

       tar2sqfs - create a SquashFS image from a tar archive

SYNOPSIS

       tar2sqfs [OPTIONS...] <sqfsfile>

DESCRIPTION

       Quickly and painlessly turn a tar ball into a SquashFS filesystem image.

       By default, the program reads the archive from standard input. Compressed archives are supported.

       Possible options:

       --root-becomes, -r <dir>
              If  set, only pack entries that are underneath the specified directory. The prefix is stripped and
              the meta data for the  directory  itself  is  copied  to  the  root  inode  (i.e.  the  ownership,
              permissions, extended attributes, modification time).

              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 /).

       --no-symlink-retarget, -S
              If  --root-becomes  is  used,  link targets are adjusted if they are prefixed by the root path. By
              default, this is also done on symbolic links, that have a target that is prefixed by the root path
              and they are converted to aboluste paths with the prefix removed. However,  because  symlinks  can
              point across mount points, this may actually be intended for some use cases.

              This flag allows changing the default behaviour, so only hard links are retargeted.

       --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  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 (unless --root-becomes is used) and
              the modification time on the SquashFS image itself will 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.

       --no-tail-packing, -T
              Do not perform tail end packing on files that are larger than the specified block size.

       --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. Global PAX headers are ignored.

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

       The input tar file can either be uncompressed, or stream compressed using gzip, xz, zstd  or  bzip2.  The
       program transparently auto-detects and unpacks any stream compressed archive. The exact list of supported
       compressors depends on the compile configuration.

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

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)