Devuan fork of gpsd
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  1. '\" t
  2. .\" Title: ntpshmmon
  3. .\" Author: [see the "AUTHOR" section]
  4. .\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
  5. .\" Date: 21 Dec 2018
  6. .\" Manual: GPSD Documentation
  7. .\" Source: The GPSD Project
  8. .\" Language: English
  9. .\"
  10. .TH "NTPSHMMON" "1" "21 Dec 2018" "The GPSD Project" "GPSD Documentation"
  11. .\" -----------------------------------------------------------------
  12. .\" * Define some portability stuff
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  15. .\" http://bugs.debian.org/507673
  16. .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
  17. .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  18. .ie \n(.g .ds Aq \(aq
  19. .el .ds Aq '
  20. .\" -----------------------------------------------------------------
  21. .\" * set default formatting
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  23. .\" disable hyphenation
  24. .nh
  25. .\" disable justification (adjust text to left margin only)
  26. .ad l
  27. .\" -----------------------------------------------------------------
  28. .\" * MAIN CONTENT STARTS HERE *
  29. .\" -----------------------------------------------------------------
  30. .SH "NAME"
  31. ntpshmmon \- capture samples from gpsd or other ntpd refclock sources
  32. .SH "SYNOPSIS"
  33. .HP \w'\fBntpshmmon\fR\ 'u
  34. \fBntpshmmon\fR [\-?] [\-h] [\-n\ \fInsamples\fR] [\-o] [\-s] [\-t\ \fInseconds\fR] [\-v] [\-V]
  35. .SH "DESCRIPTION"
  36. .PP
  37. This program monitors the shared\-memory segments updated by
  38. \fBgpsd\fR(8)
  39. , and possibly other refclock sources, as a way of communicating with ntpd, the Network Time Protocol daemon\&. It reads these in exactly the way an ntpd instance does\&. It can be run concurrently with ntpd without interfering with ntpd\*(Aqs normal operation\&.
  40. .PP
  41. This program runs forever, or until a termination option is matched, or until interrupted, generating sample reports to standard output\&. Each line consists of whitespace\-separated textual fields\&.
  42. .PP
  43. Here is an example of the beginning of a report file:
  44. .sp
  45. .if n \{\
  46. .RS 4
  47. .\}
  48. .nf
  49. ntpshmmon version 3\&.18
  50. # Name Seen@ Clock Real L Pre
  51. sample NTP2 1424926256\&.443030206 1424926256\&.115869233 1424926256\&.000000000 0 \-1
  52. sample NTP3 1424926256\&.443060517 1424926255\&.995430821 1424926256\&.000000000 0 \-20
  53. sample NTP3 1424926256\&.995747347 1424926256\&.995422728 1424926257\&.000000000 0 \-20
  54. sample NTP2 1424926257\&.112433572 1424926257\&.111936726 1424926257\&.000000000 0 \-1
  55. sample NTP3 1424926257\&.996221153 1424926257\&.995410232 1424926258\&.000000000 0 \-20
  56. sample NTP2 1424926258\&.107769409 1424926258\&.107451006 1424926258\&.000000000 0 \-1
  57. sample NTP3 1424926258\&.995647636 1424926258\&.995406476 1424926259\&.000000000 0 \-20
  58. .fi
  59. .if n \{\
  60. .RE
  61. .\}
  62. .PP
  63. The output always begins with a header line expressing the version of the output format; the version line begins with "ntpshmmon version" and is followed by a numeric version field\&.
  64. .PP
  65. The remainder of the file is either commments or sample lines\&. A comment line begins with a # and should ignored by programs that interpret this format\&.
  66. .PP
  67. The fields of a sample line are as follows:
  68. .sp
  69. .RS 4
  70. .ie n \{\
  71. \h'-04' 1.\h'+01'\c
  72. .\}
  73. .el \{\
  74. .sp -1
  75. .IP " 1." 4.2
  76. .\}
  77. The keyword "sample"
  78. .RE
  79. .sp
  80. .RS 4
  81. .ie n \{\
  82. \h'-04' 2.\h'+01'\c
  83. .\}
  84. .el \{\
  85. .sp -1
  86. .IP " 2." 4.2
  87. .\}
  88. The NTP unit from which it was collected\&.
  89. .RE
  90. .sp
  91. .RS 4
  92. .ie n \{\
  93. \h'-04' 3.\h'+01'\c
  94. .\}
  95. .el \{\
  96. .sp -1
  97. .IP " 3." 4.2
  98. .\}
  99. Collection time of day, seconds\&.
  100. .RE
  101. .sp
  102. .RS 4
  103. .ie n \{\
  104. \h'-04' 4.\h'+01'\c
  105. .\}
  106. .el \{\
  107. .sp -1
  108. .IP " 4." 4.2
  109. .\}
  110. Receiver time of day, seconds\&.
  111. .RE
  112. .sp
  113. .RS 4
  114. .ie n \{\
  115. \h'-04' 5.\h'+01'\c
  116. .\}
  117. .el \{\
  118. .sp -1
  119. .IP " 5." 4.2
  120. .\}
  121. Clock time of day, seconds\&.
  122. .RE
  123. .sp
  124. .RS 4
  125. .ie n \{\
  126. \h'-04' 6.\h'+01'\c
  127. .\}
  128. .el \{\
  129. .sp -1
  130. .IP " 6." 4.2
  131. .\}
  132. Leap\-second notification status\&.
  133. .RE
  134. .sp
  135. .RS 4
  136. .ie n \{\
  137. \h'-04' 7.\h'+01'\c
  138. .\}
  139. .el \{\
  140. .sp -1
  141. .IP " 7." 4.2
  142. .\}
  143. Source precision (log(2) of source jitter)\&.
  144. .RE
  145. .PP
  146. In these fields, "clock time" is the high\-precision system clock time measured by the source and "receiver time" is from the receiver\&. Both times are in UTC\&. It is normal for the seconds part of receiver time to coincide with the seconds part of collection time and for the nanoseconds part of receiver time to be zero\&.
  147. .PP
  148. If the \-o option is used, the "Seen@" column is replaced with the "Offset" column\&. The "Offset" is the difference between "Clock" and "Real" times\&.
  149. .SH "OPTIONS"
  150. .PP
  151. \-?
  152. .RS 4
  153. Display program usage and exit\&.
  154. .RE
  155. .PP
  156. \-h
  157. .RS 4
  158. Display program usage and exit\&.
  159. .RE
  160. .PP
  161. \-n
  162. .RS 4
  163. Set maximum number of samples to collect\&.
  164. .RE
  165. .PP
  166. \-o
  167. .RS 4
  168. Replace the "Seen@" column with the "Offset" column\&. The "Offset" is the difference between "Clock" and "Real" times\&.
  169. .RE
  170. .PP
  171. \-s
  172. .RS 4
  173. Remove all SHM segments used by GPSD\&. This option will normally only be of interest to GPSD developers\&.
  174. .RE
  175. .PP
  176. \-t
  177. .RS 4
  178. Set maximum time to collect samples in seconds\&.
  179. .RE
  180. .PP
  181. \-v
  182. .RS 4
  183. Enable verbose status messages\&.
  184. .RE
  185. .PP
  186. \-V
  187. .RS 4
  188. Display program version and exit\&.
  189. .RE
  190. .SH "SEE ALSO"
  191. .PP
  192. \fBgpsd\fR(8),
  193. \fBgpsdctl\fR(8),
  194. \fBgps\fR(1),
  195. \fBlibgps\fR(3),
  196. \fBlibgpsmm\fR(3),
  197. \fBgpsprof\fR(1),
  198. \fBgpsfake\fR(1)\&.
  199. .SH "AUTHOR"
  200. .PP
  201. Eric S\&. Raymond
  202. <esr@thyrsus\&.com>\&.