xref: /freebsd/sbin/conscontrol/conscontrol.8 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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2.\" Copyright (c) 2001 Jonathan Lemon <jlemon@FreeBSD.org>
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26.\" $FreeBSD$
27.\"
28.Dd April 14, 2011
29.Dt CONSCONTROL 8
30.Os
31.Sh NAME
32.Nm conscontrol
33.Nd control physical console devices
34.Sh SYNOPSIS
35.Nm
36.Op Cm list
37.Nm
38.Cm mute on | off
39.Nm
40.Cm add | delete
41.Ar console
42.Nm
43.Cm set | unset Ar console
44.Sh DESCRIPTION
45The
46.Nm
47utility is used to examine and modify the physical devices which back
48the virtual console devices.
49If no arguments
50(or only the
51.Cm list
52command)
53are specified,
54the current console settings are shown.
55.Pp
56There are two types of logical consoles; a high level console which
57is represented by
58.Pa /dev/console ,
59and a low level console.
60The low level console is used for kernel
61.Xr printf 9
62and
63.Xr ddb 4
64debugger support,
65while the high level console is used by user programs like
66.Xr syslogd 8 .
67Multiple device support is implemented only for the low level console;
68the high level console is set to the first device in the console list.
69.Pp
70Multiple console support may be invoked by passing the kernel the
71.Fl D
72flag from the boot loader, or by using
73.Nm
74to change the list of console devices after the system has booted.
75.Pp
76The following options are available:
77.Bl -tag -width indent
78.It Cm add | delete Ar console
79Add or delete a physical device from the logical console.
80The device must support low-level console operations.
81Adding a device will place it at the front of the list of console
82devices; the first device is used for the high level console.
83.Pp
84The
85.Ar console
86argument
87is the name of a console device in
88.Pa /dev ;
89the name of the directory may be omitted.
90.It Cm mute on | off
91Change the state of console muting.
92All console output is suppressed when console muting is
93.Cm on .
94.It Cm set | unset Ar console
95Set or unset the virtual console.
96When unset, output from the system, such as the kernel
97.Xr printf 9 ,
98always goes out to the real main console.
99When set, it goes to another.
100This is an interface to the tty ioctl
101.Dv TIOCCONS .
102.El
103.Sh SEE ALSO
104.Xr syscons 4 ,
105.Xr tty 4 ,
106.Xr vt 4 ,
107.Xr boot 8 ,
108.Xr loader 8
109.Sh HISTORY
110The
111.Nm
112utility first appeared in
113.Fx 5.0 .
114.Sh AUTHORS
115.An Jonathan Lemon
116