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  1. .\" -*- nroff -*-
  2. .Dd August 4, 2018
  3. .Os GNU/Linux
  4. .Dt LIGHT 1 URM
  5. .Sh NAME
  6. .Nm light
  7. .Nd a program to control backlight controllers
  8. .Sh SYNOPSIS
  9. .Nm light
  10. .Op Fl abcGhHkIlLmOprV
  11. .Op Fl s Ar ARG
  12. .Op Fl v Ar LEVEL
  13. .Op Fl A Ar VAL
  14. .Op Fl S Ar VAL
  15. .Op Fl U Ar VAL
  16. .Sh DESCRIPTION
  17. .Nm
  18. is a program to control backlight display and keyboard controllers under
  19. GNU/Linux.
  20. .Pp
  21. .Bl -bullet -compact
  22. .It
  23. Operates independently of X (X-Window)
  24. .It
  25. Can automatically figure out the best controller to use, making full use
  26. of the underlying hardware
  27. .It
  28. Supports a minimum cap on the brightness value, as some controllers set
  29. the display to be pitch black at a vaĺue of 0 (or higher)
  30. .El
  31. .Sh COMMANDS
  32. The following unique commands are supported:
  33. .Pp
  34. .Bl -tag -width Ds
  35. .It Fl A Ar VAL
  36. Add value
  37. .It Fl G
  38. Get value, default
  39. .It Fl H , Fl h
  40. Show help text and exit
  41. .It Fl I
  42. Restore brightness
  43. .It Fl L
  44. List controllers
  45. .It Fl O
  46. Save brightness
  47. .It Fl S Ar VAL
  48. Set value
  49. .It Fl U Ar VAL
  50. Subtract value
  51. .It Fl V
  52. Show program version and exit
  53. .El
  54. .Sh OPTIONS
  55. The behavior of the above commands can be modified using these options:
  56. .Pp
  57. .Bl -tag -width Ds
  58. .It Fl b
  59. Set
  60. .Fl S ,
  61. Get
  62. .Fl G ,
  63. Add
  64. .Fl A ,
  65. or Subtract
  66. .Fl U
  67. active brightness, default
  68. .It Fl k
  69. Act on keyboard backlight
  70. .It Fl l
  71. Act on display backlight, default
  72. .It Fl m
  73. Get
  74. .Fl G
  75. maximum brightness
  76. .It Fl c
  77. Set
  78. .Fl S
  79. or get
  80. .Fl G
  81. minimum cap for brightness
  82. .It Fl a
  83. Select controller automatically, default
  84. .It Fl p
  85. Interpret input and output values in percent, default
  86. .It Fl r
  87. Interpret input and output values in raw mode
  88. .It Fl s Ar ARG
  89. Specify controller to use. Use
  90. .Fl L
  91. to list available controllers
  92. .It Fl v Ar ARG
  93. Set verbosity level, by default
  94. .Nm
  95. only outputs read values:
  96. .Pp
  97. .Bl -tag -width 0: -compact
  98. .It 0:
  99. Read values
  100. .It 1:
  101. Read values, Errors
  102. .It 2:
  103. Read values, Errors, Warnings
  104. .It 3:
  105. Read values, Errors, Warnings, Notices
  106. .El
  107. .El
  108. .Sh FILES
  109. When run in its classic SUID root mode
  110. .Nm
  111. caches settings and current brightness in
  112. .Pa /etc/light .
  113. In its non-priviliged mode of operation the
  114. .Pa ~/.cache/light
  115. directory is used instead.
  116. .Sh AUTHORS
  117. Copyright \(co 2014 Fredrik Haikarainen
  118. .Pp
  119. This is free software, see the source for copying conditions. There is NO
  120. warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE