.\"	$OpenBSD: kdump.1,v 1.37 2023/04/17 05:43:12 jmc Exp $
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.\"	from: @(#)kdump.1	8.1 (Berkeley) 6/6/93
.\"
.Dd $Mdocdate: April 17 2023 $
.Dt KDUMP 1
.Os
.Sh NAME
.Nm kdump
.Nd display kernel trace data
.Sh SYNOPSIS
.Nm kdump
.Op Fl dHlnRTXx
.Op Fl f Ar file
.Op Fl m Ar maxdata
.Op Fl p Ar pid
.Op Fl t Ar trstr
.Op Fl u Ar label
.Sh DESCRIPTION
.Nm
displays the kernel trace files produced with
.Xr ktrace 1
in human-readable format.
By default, the file
.Pa ktrace.out
in the current directory is displayed, unless overridden by the
.Fl f
option.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl d
Display all numbers in decimal.
By default, values are printed out in hexadecimal.
.It Fl f Ar file
Display the specified file instead of
.Pa ktrace.out .
Specifying
.Sq -
will read from standard input.
.It Fl H
Display thread identifiers.
.It Fl l
Loop reading the trace file, once the end-of-file is reached, waiting for
more data.
.It Fl m Ar maxdata
Display at most
.Ar maxdata
bytes when decoding I/O.
.It Fl n
Suppress ad hoc translations.
Normally
.Nm
tries to decode many system calls into a more human-readable format.
For example,
.Xr ioctl 2
values are replaced with the macro name and
.Va errno
values are replaced with the
.Xr strerror 3
string.
Suppressing this feature yields a more consistent output format and is
easily amenable to further processing.
.It Fl p Ar pid
Show output only for the
.Ar pid
specified.
.It Fl R
Display relative timestamps (time since previous entry).
.It Fl T
Display absolute timestamps for each entry (seconds since the Epoch).
.It Fl TR
If both options are specified, display timestamps relative to trace start.
.It Fl t Ar trstr
Select which tracepoints to display.
The argument can contain one or more of the letters
.Cm cinpstuxX+ .
See the
.Fl t
option of
.Xr ktrace 1
for the meaning of the letters.
.It Fl u Ar label
Display
.Xr utrace 2
tracepoints having
.Xr utrace 2
label
.Ar label
as strings with
.Xr vis 3
escaping, without
.Xr ktrace 2
header information.
.It Fl X
Display I/O data with hexadecimal data and printable ASCII characters
side by side.
.It Fl x
Display I/O data in hexadecimal.
.El
.Pp
The
.Fl t
and
.Fl u
options are mutually exclusive;
the last one specified overrides any previous ones.
.Sh FILES
.Bl -tag -width ktrace.out -compact
.It Pa ktrace.out
default ktrace dump file
.El
.Sh SEE ALSO
.Xr ktrace 1
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.3 Reno .