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tar2sqfs.1 (6193B)

    

  1. .TH TAR2SQFS "1" "June 2019" "tar2sqfs" "User Commands"
  2. .SH NAME
  3. tar2sqfs \- create a SquashFS image from a tar archive
  4. .SH SYNOPSIS
  5. .B tar2sqfs
  6. [\fI\,OPTIONS\/\fR...] \fI\,<sqfsfile>\/\fR
  7. .SH DESCRIPTION
  8. Quickly and painlessly turn a tar ball into a SquashFS filesystem image.
  9. .PP
  10. By default, the program reads the archive from standard input. Compressed
  11. archives are supported.
  12. .PP
  13. Possible options:
  14. .TP
  15. \fB\-\-root\-becomes\fR, \fB\-r\fR <dir>
  16. If set, only pack entries that are underneath the specified directory. The
  17. prefix is stripped and the meta data for the directory itself is copied to the
  18. root inode (i.e. the ownership, permissions, extended attributes,
  19. modification time).
  21. If this option is not set, tar2sqfs implicitly treats \fB./\fR or absolute
  22. paths this way, i.e. if the archive contains an entry for \fB./\fR, it becomes
  23. the root node and the prefix is stripped from all paths (and similar for
  24. absolute paths and \fB/\fR).
  25. .TP
  26. \fB\-\-no\-symlink\-retarget\fR, \fB\-S\fR
  27. If \-\-root\-becomes is used, link targets are adjusted if they are prefixed by
  28. the root path. By default, this is also done on symbolic links, that have a
  29. target that is prefixed by the root path and they are converted to aboluste
  30. paths with the prefix removed. However, because symlinks can point across mount
  31. points, this may actually be intended for some use cases.
  33. This flag allows changing the default behaviour, so only hard links are
  34. retargeted.
  35. .TP
  36. \fB\-\-compressor\fR, \fB\-c\fR <name>
  37. Select the compressor to use.
  38. Run \fBtar2sqfs \-\-help\fR to get a list of all available compressors
  39. and the default selection.
  40. .TP
  41. \fB\-\-comp\-extra\fR, \fB\-X\fR <options>
  42. A comma separated list of extra options for the selected compressor. Specify
  43. \fBhelp\fR to get a list of available options.
  44. .TP
  45. \fB\-\-num\-jobs\fR, \fB\-j\fR <count>
  46. If libsquashfs was compiled with a thread pool based, parallel data
  47. compressor, this option can be used to set the number of compressor
  48. threads. If not set, the default is the number of available CPU cores.
  49. .TP
  50. \fB\-\-queue\-backlog\fR, \fB\-Q\fR <count>
  51. Maximum number of data blocks in the thread worker queue before the packer
  52. starts waiting for the block processors to catch up. Higher values result
  53. in higher memory consumption. Defaults to 10 times the number of workers.
  54. .TP
  55. \fB\-\-block\-size\fR, \fB\-b\fR <size>
  56. Block size to use for SquashFS image.
  57. Defaults to 131072.
  58. .TP
  59. \fB\-\-dev\-block\-size\fR, \fB\-B\fR <size>
  60. Device block size to padd the image to.
  61. Defaults to 4096.
  62. .TP
  63. \fB\-\-defaults\fR, \fB\-d\fR <options>
  64. A comma separated list of default values for
  65. implicitly created directories.
  66. The following values can be set:
  67. .TS
  68. tab(;) allbox;
  69. l l
  70. l l
  71. l l
  72. l l
  73. l l
  74. rd.
  75. \fBOption\fR;\fBDefault\fR
  76. uid=<value>;0
  77. gid=<value>;0
  78. mode=<value>;0755
  79. mtime=<value>;\fB$SOURCE\_DATE\_EPOCH\fR if set, 0 otherwise
  80. .TE
  81. .TP
  82. .TP
  83. \fB\-\-no\-keep\-time\fR, \fB\-k\fR
  84. Replace the time stamps from the tar archive with default time stamps for all
  85. entries.
  87. The default behavior is to preserve the time stamps from the archive to the
  88. extent possible (SquashFS has second resolution and 32 bit time stamps; tar can
  89. use extensions to specify much larger timestamps with arbitrary precision). The
  90. root inode (unless \fB\-\-root\-becomes\fR is used) and the modification time on
  91. the SquashFS image itself will still be set to defaults.
  92. .TP
  93. \fB\-\-no\-xattr\fR, \fB\-x\fR
  94. Do not copy extended attributes from archive. Default behaviour is to copy all
  95. extended attributes and skip the ones that cannot be encoded in SquashFS.
  96. .TP
  97. \fB\-\-no\-skip\fR, \fB\-s\fR
  98. Abort if a tar record cannot be read instead of skipping it.
  99. .TP
  100. \fB\-\-exportable\fR, \fB\-e\fR
  101. Generate an export table for NFS support.
  102. .TP
  103. \fB\-\-no\-tail\-packing\fR, \fB\-T\fR
  104. Do not perform tail end packing on files that are larger than the
  105. specified block size.
  106. .TP
  107. \fB\-\-force\fR, \fB\-f\fR
  108. Overwrite the output file if it exists.
  109. .TP
  110. \fB\-\-quiet\fR, \fB\-q\fR
  111. Do not print out progress reports.
  112. .TP
  113. \fB\-\-help\fR, \fB\-h\fR
  114. Print help text and exit.
  115. .TP
  116. \fB\-\-version\fR, \fB\-V\fR
  117. Print version information and exit.
  118. .SH COMPATIBILITY
  119. Currently the program can process v7 format, pre-POSIX ustar, POSIX tar and GNU
  120. tar archives. PAX extension headers are also supported. Global PAX headers are
  121. ignored.
  123. The support for GNU tar is limited to a commonly used subset (i.e. some legacy
  124. extensions that GNU tar itself no longer generates are not supported; neither
  125. are multi volume archives).
  127. The input tar file can either be uncompressed, or stream compressed using
  128. \fBgzip\fR, \fBxz\fR, \fBzstd\fR or \fBbzip2\fR. The program transparently
  129. auto-detects and unpacks any stream compressed archive. The exact list of
  130. supported compressors depends on the compile configuration.
  132. Extended attributes are supported through the \fBSCHILY.xattr\fR extension
  133. (favoured by GNU tar and star) or through the \fBLIBARCHIVE.xattr\fR extension.
  135. If any unsupported section or extended attribute key is encountered in an
  136. archive, a warning message is written to stderr. If the \fB\-\-no\-skip\fR
  137. option is set, processing aborts. By default, unknown sections and unsupported
  138. extended attributes are simply skipped after issuing a warning.
  139. .SH ENVIRONMENT
  140. If the command line switch \fB\-\-defaults\fR is not used or no default mtime
  141. is specified, the value of the environment variable \fBSOURCE\_DATE\_EPOCH\fR
  142. is used for all file and filesystem timestamps.
  144. If \fBSOURCE\_DATE\_EPOCH\fR is not set, not a parsable number or it is out of
  145. range, the timestamps default to 0.
  147. Environment variables are only used if no explicit command line switches
  148. are set. Explicit command line switches are always preferred over the
  149. environment variables.
  150. .SH EXAMPLES
  151. .TP
  152. Turn an uncompressed tar archive into a SquashFS image:
  153. .IP
  154. tar2sqfs rootfs.sqfs < rootfs.tar.gz
  155. .SH SEE ALSO
  156. gensquashfs(1), rdsquashfs(1), sqfs2tar(1)
  157. .SH AUTHOR
  158. Written by David Oberhollenzer.
  159. .SH COPYRIGHT
  160. Copyright \(co 2019 David Oberhollenzer
  161. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
  162. .br
  163. This is free software: you are free to change and redistribute it.
  164. There is NO WARRANTY, to the extent permitted by law.