xref: /freebsd/sbin/conscontrol/conscontrol.8 (revision 2008043f386721d58158e37e0d7e50df8095942d)
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26.Dd April 14, 2011
27.Dt CONSCONTROL 8
28.Os
29.Sh NAME
30.Nm conscontrol
31.Nd control physical console devices
32.Sh SYNOPSIS
33.Nm
34.Op Cm list
35.Nm
36.Cm mute on | off
37.Nm
38.Cm add | delete
39.Ar console
40.Nm
41.Cm set | unset Ar console
42.Sh DESCRIPTION
43The
44.Nm
45utility is used to examine and modify the physical devices which back
46the virtual console devices.
47If no arguments
48(or only the
49.Cm list
50command)
51are specified,
52the current console settings are shown.
53.Pp
54There are two types of logical consoles; a high level console which
55is represented by
56.Pa /dev/console ,
57and a low level console.
58The low level console is used for kernel
59.Xr printf 9
60and
61.Xr ddb 4
62debugger support,
63while the high level console is used by user programs like
64.Xr syslogd 8 .
65Multiple device support is implemented only for the low level console;
66the high level console is set to the first device in the console list.
67.Pp
68Multiple console support may be invoked by passing the kernel the
69.Fl D
70flag from the boot loader, or by using
71.Nm
72to change the list of console devices after the system has booted.
73.Pp
74The following options are available:
75.Bl -tag -width indent
76.It Cm add | delete Ar console
77Add or delete a physical device from the logical console.
78The device must support low-level console operations.
79Adding a device will place it at the front of the list of console
80devices; the first device is used for the high level console.
81.Pp
82The
83.Ar console
84argument
85is the name of a console device in
86.Pa /dev ;
87the name of the directory may be omitted.
88.It Cm mute on | off
89Change the state of console muting.
90All console output is suppressed when console muting is
91.Cm on .
92.It Cm set | unset Ar console
93Set or unset the virtual console.
94When unset, output from the system, such as the kernel
95.Xr printf 9 ,
96always goes out to the real main console.
97When set, it goes to another.
98This is an interface to the tty ioctl
99.Dv TIOCCONS .
100.El
101.Sh SEE ALSO
102.Xr syscons 4 ,
103.Xr tty 4 ,
104.Xr vt 4 ,
105.Xr boot 8 ,
106.Xr loader 8
107.Sh HISTORY
108The
109.Nm
110utility first appeared in
111.Fx 5.0 .
112.Sh AUTHORS
113.An Jonathan Lemon
114