# UTMPDUMP - dump UTMP and WTMP files in raw format - man(1) - [phpMan]

> **TLDR:** Dump and load btmp, utmp, and wtmp accounting files.
>
- Dump the `/var/log/wtmp` file to `stdout` as plain text:
  `utmpdump {{/var/log/wtmp}}`
- Load a previously dumped file into `/var/log/wtmp`:
  `utmpdump {{-r|--reverse}} {{dumpfile}} > {{/var/log/wtmp}}`

*Source: tldr-pages*

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[_UTMPDUMP_(1)](https://www.chedong.com/phpMan.php/man/UTMPDUMP/1/markdown)                                 User Commands                                [_UTMPDUMP_(1)](https://www.chedong.com/phpMan.php/man/UTMPDUMP/1/markdown)

## NAME
       utmpdump - dump UTMP and WTMP files in raw format

## SYNOPSIS
       **utmpdump **[options] _filename_

## DESCRIPTION
       **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.

## OPTIONS
### -f --follow
           Output appended data as the file grows.

### -o --output 
           Write command output to _file_ instead of standard output.

### -r --reverse
           Undump, write back edited login information into the utmp or wtmp files.

### -h --help
           Display help text and exit.

### -V --version
           Print version and exit.

## NOTES
       **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:

          **utmpdump -r < ascii_file > wtmp**

       But be warned, **utmpdump **was written for debugging purposes only.

### File formats
       Only the binary version of the [**utmp**(5)](https://www.chedong.com/phpMan.php/man/utmp/5/markdown) is standardised. Textual dumps may become incompatible
       in future.

       The version 2.28 was the last one that printed text output using [**ctime**(3)](https://www.chedong.com/phpMan.php/man/ctime/3/markdown) 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.

## BUGS
       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.

## AUTHORS
       Michael Krapp

## SEE ALSO
       [**last**(1)](https://www.chedong.com/phpMan.php/man/last/1/markdown), [**w**(1)](https://www.chedong.com/phpMan.php/man/w/1/markdown), [**who**(1)](https://www.chedong.com/phpMan.php/man/who/1/markdown), [**utmp**(5)](https://www.chedong.com/phpMan.php/man/utmp/5/markdown)

## REPORTING BUGS
       For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
       The **utmpdump **command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <<https://www.kernel.org/pub/linux/utils/util-linux/>>.

util-linux 2.39.3                            2023-10-23                                  [_UTMPDUMP_(1)](https://www.chedong.com/phpMan.php/man/UTMPDUMP/1/markdown)