KDUMP(1) | General Commands Manual | KDUMP(1)

# NAME

`kdump` — display kernel trace data

# SYNOPSIS

`kdump` | [`-dElNnRT`] [`-e` emulation] [`-f` file] [`-m` maxdata] [`-p` pid] [`-t` trstr] [`-x` | `-X` size] [file]

# DESCRIPTION

`kdump` displays the kernel trace files produced with ktrace(1) in human readable format. The file ktrace.out in the current directory is displayed, unless either the `-f` option is used, or a file name is supplied as the last argument.

The options are as follows:

`-d`
  Display all numbers in decimal.
`-E`
  Display elapsed timestamps (time since beginning of trace).
`-e` emulation
  If an emulation of a process is unknown, interpret system call maps assuming the named emulation instead of default "netbsd".
`-f` file
  Display the specified file instead of ktrace.out.
`-l`
  Loop reading the trace file, once the end-of-file is reached, waiting for more data.
`-m` maxdata
  Display at most maxdata bytes when decoding I/O.
`-N`
  Suppress system call number-to-name translation.
`-n`
  Suppress ad hoc translations. Normally `kdump` tries to decode many system calls into a more human readable format. For example, ioctl(2) values are replaced with the macro name and errno values are replaced with the strerror(3) string. Suppressing this feature yields a more consistent output format and is easily amenable to further processing.
`-p` pid
  Only display records from the trace file that are for the indicated pid.
`-R`
  Display relative timestamps (time since previous entry).
`-T`
  Display absolute timestamps for each entry (seconds since epoch).
`-t` trstr
  Restrict display to the specified set of kernel trace points. The default is to display everything in the file. See the `-t` option of ktrace(1).
`-x`
  Display GIO data in hex and ascii instead of vis(3) format.
`-X` size
  Same as `-x` but display hex values by groups of size bytes. Supported values are 1, 2, 4, 8, and 16.

# SEE ALSO

ioctlprint(1), ktrace(1)

# HISTORY

The `kdump` command appeared in 4.4BSD.

April 2, 2020 | NetBSD 11.0