freebsd-nq/sbin/ddb/ddb.8

.\"-
.\" Copyright (c) 2007 Robert N. M. Watson
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.Dd 25 December, 2007
.Dt DDB 8
.Os
.Sh NAME
.Nm ddb
.Nd Configure DDB kernel debugger properties
.Sh SYNOPSIS
.Nm
.Cm script
.Ar scriptname
.Nm
.Cm script
.Ar scriptname=script
.Nm
.Cm scripts
.Nm
.Cm unscript
.Ar scriptname
.Sh DESCRIPTION
.Nm
configures certain aspects of the
.Xr DDB 4
kernel debugger from user space that are not configured at compile-time or
easily via
.Xr sysctl 8
MIB entries.
.Sh SCRIPTING
.Nm
can be used to configure aspects of
.Xr DDB 4
scripting from user space; scripting support is described in more detail in
.Xr DDB 4 .
Each of the debugger commands is available from the command line:
.Bl -tag -width indent
.It Cm script Ar scriptname
Print the script named
.Ar scriptname .
.It Cm script Ar scriptname=scriptvalue
Define a script named
.Ar scriptname ;
as many scripts contain characters interpreted in special ways by the shell,
it is advisable to enclose
.Ar scriptvalue
in quotes.
.It Cm scripts
List currently defined scripts.
.It Cm unset Ar scriptname
Delete the script named
.Ar scriptname .
.El
.Sh EXAMPLES
The following example defines a script that will execute when the kernel
debugger is entered as a result of a break signal:
.Bd -literal -offset indent
ddb script kdb.enter.break="show pcpu; bt"
.Ed
.Pp
The following example will delete the script:
.Bd -literal -offset indent
ddb unscript kdb.enter.break
.Ed
.Pp
For further examples, see the
.Xr ddb 4
and
.Xr textdump 4
man pages.
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr ddb 4 ,
.Xr textdump 4 ,
.Xr sysctl 8
.Sh HISTORY
.Nm
first appeared in
.Fx 8.0 .
.Sh AUTHORS
.An Robert N M Watson
.Sh BUGS
Ideally,
.Nm
would not exist, as all pertinent aspects of
.Xr ddb 4
could be configured directly via
.Xr sysctl 8 .