login-utils/utmpdump.1.adoc

   1 //po4a: entry man manual
   2 ////
   3 Copyright (C) 2010 Michael Krapp
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18 ////
  19 = utmpdump(1)
  20 :doctype: manpage
  21 :man manual: User Commands
  22 :man source: util-linux {release-version}
  23 :page-layout: base
  24 :command: utmpdump
  25
  26 == NAME
  27
  28 utmpdump - dump UTMP and WTMP files in raw format
  29
  30 == SYNOPSIS
  31
  32 *utmpdump* [options] _filename_
  33
  34 == DESCRIPTION
  35
  36 *utmpdump* is a simple program to dump UTMP and WTMP files in raw format, so they can be examined. *utmpdump* reads from stdin unless a _filename_ is passed.
  37
  38 == OPTIONS
  39
  40 *-f*, *--follow*::
  41 Output appended data as the file grows.
  42
  43 *-o*, *--output* _file_::
  44 Write command output to _file_ instead of standard output.
  45
  46 *-r*, *--reverse*::
  47 Undump, write back edited login information into the utmp or wtmp files.
  48
  49 *-V*, *--version*::
  50 Display version information and exit.
  51
  52 *-h*, *--help*::
  53 Display help text and exit.
  54
  55 == NOTES
  56
  57 *utmpdump* can be useful in cases of corrupted utmp or wtmp entries. It can dump out utmp/wtmp to an ASCII file, which can then be edited to remove bogus entries, and reintegrated using:
  58
  59 ____
  60 *utmpdump -r < ascii_file > wtmp*
  61 ____
  62
  63 But be warned, *utmpdump* was written for debugging purposes only.
  64
  65 === File formats
  66
  67 Only the binary version of the *utmp*(5) is standardised. Textual dumps may become incompatible in future.
  68
  69 The version 2.28 was the last one that printed text output using *ctime*(3) timestamp format. Newer dumps use millisecond precision ISO-8601 timestamp format in UTC-0 timezone. Conversion from former timestamp format can be made to binary, although attempt to do so can lead the timestamps to drift amount of timezone offset.
  70
  71 == BUGS
  72
  73 You may *not* use the *-r* option, as the format for the utmp/wtmp files strongly depends on the input format. This tool was *not* written for normal use, but for debugging only.
  74
  75 == AUTHORS
  76
  77 Michael Krapp
  78
  79 == SEE ALSO
  80
  81 *last*(1),
  82 *w*(1),
  83 *who*(1),
  84 *utmp*(5)
  85
  86 include::man-common/bugreports.adoc[]
  87
  88 include::man-common/footer.adoc[]
  89
  90 ifdef::translation[]
  91 include::man-common/translation.adoc[]
  92 endif::[]