gzip 3.2 KB

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  1. .TH GZIP 1
  2. .SH NAME
  3. gzip, gunzip, bzip2, bunzip2, zip, unzip, \- compress and expand data
  4. .SH SYNOPSIS
  5. .B gzip
  6. .RB [ -cvD [ 1-9 ]]
  7. .RI [ file
  8. .BR ... ]
  9. .PP
  10. .B gunzip
  11. .RB [ -ctTvD ]
  12. .RI [ file
  13. .BR ... ]
  14. .PP
  15. .B bzip2
  16. .RB [ -cvD [ 1-9 ]]
  17. .RI [ file
  18. .BR ... ]
  19. .PP
  20. .B bunzip2
  21. .RB [ -cvD ]
  22. .RI [ file
  23. .BR ... ]
  24. .PP
  25. .B zip
  26. .RB [ -vD [ 1-9 ]]
  27. .RB [ -f
  28. .IR zipfile ]
  29. .I file
  30. .RB [ ... ]
  31. .PP
  32. .B unzip
  33. .RB [ -cistTvD ]
  34. .RB [ -f
  35. .IR zipfile ]
  36. .IR [ file
  37. .BR ... ]
  38. .SH DESCRIPTION
  39. .PP
  40. .I Gzip
  41. encodes files with a hybrid Lempel-Ziv 1977 and Huffman compression algorithm
  42. known as
  43. .BR deflate .
  44. Most of the time, the resulting file is smaller,
  45. and will never be much bigger.
  46. Output files are named by taking the last path element of each file argument
  47. and appending
  48. .BR .gz ;
  49. if the resulting name ends with
  50. .BR .tar.gz ,
  51. it is converted to
  52. .B .tgz
  53. instead.
  54. .I Gunzip
  55. reverses the process.
  56. Its output files are named by taking the last path element of each file argument,
  57. converting
  58. .B .tgz
  59. to
  60. .BR .tar.gz ,
  61. and stripping any
  62. .BR .gz ;
  63. the resulting name must be different from the original name.
  64. .PP
  65. .I Bzip2
  66. and
  67. .I bunzip2
  68. are similar in interface to
  69. .I gzip
  70. and
  71. .IR gunzip ,
  72. but use a modified Burrows-Wheeler block sorting
  73. compression algorithm.
  74. The default suffix for output files is
  75. .BR .bz2 ,
  76. with
  77. .B .tar.bz2
  78. becoming
  79. .BR .tbz .
  80. .I Bunzip2
  81. recognizes the extension
  82. .B .tbz2
  83. as a synonym for
  84. .BR .tbz .
  85. .PP
  86. .I Zip
  87. encodes the named files and places the results into the archive
  88. .IR zipfile ,
  89. or the standard output if no file is given.
  90. .I Unzip
  91. extracts files from an archive created by
  92. .IR zip .
  93. If no files are named as arguments, all of files in the archive are extracted.
  94. A directory's name implies all recursively contained files and subdirectories.
  95. .PP
  96. None of these programs removes the original files.
  97. If the process fails, the faulty output files are removed.
  98. .PP
  99. The options are:
  100. .TP 1i
  101. .B -c
  102. Write to standard output rather than creating an output file.
  103. .TP
  104. .B -i
  105. Convert all archive file names to lower case.
  106. .TP
  107. .B -s
  108. Streaming mode. Looks at the file data adjacent to each compressed file
  109. rather than seeking in the central file directory.
  110. This is the mode used by
  111. .I unzip
  112. if no
  113. .I zipfile
  114. is specified.
  115. If
  116. .B -s
  117. is given,
  118. .B -T
  119. is ignored.
  120. .TP
  121. .B -t
  122. List matching files in the archive rather than extracting them.
  123. .TP
  124. .B -T
  125. Set the output time to that specified in the archive.
  126. .TP
  127. .BR -1 " .. " -9
  128. Sets the compression level.
  129. .B -1
  130. is tuned for speed,
  131. .B -9
  132. for minimal output size.
  133. The best compromise is
  134. .BR -6 ,
  135. the default.
  136. .TP
  137. .B -v
  138. Produce more descriptive output.
  139. With
  140. .BR -t ,
  141. adds the uncompressed size in bytes and the modification time to the output.
  142. Without
  143. .BR -t ,
  144. prints the names of files on standard error as they are compressed or decompressed.
  145. .TP
  146. .B -D
  147. Produce debugging output.
  148. .SH SOURCE
  149. .B /sys/src/cmd/gzip
  150. .br
  151. .B /sys/src/cmd/bzip2
  152. .SH SEE ALSO
  153. .IR tar (1),
  154. .IR compress (1)
  155. .SH BUGS
  156. .I Unzip
  157. can only extract files which are uncompressed or compressed
  158. with the
  159. .B deflate
  160. compression scheme. Recent zip files fall into this category.
  161. Very recent zip files may have tables of contents that
  162. .I unzip
  163. cannot read. Such files are still readable by invoking
  164. .I unzip
  165. with the
  166. .B -s
  167. option.