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Manual Pages  — CONSCONTROL


conscontrol – control physical console devices



conscontrol [ list]
conscontrol mute on | off
conscontrol add | delete console
conscontrol set | unset console


The conscontrol utility is used to examine and modify the physical devices which back the virtual console devices. If no arguments (or only the list command) are specified, the current console settings are shown.

There are two types of logical consoles; a high level console which is represented by /dev/console, and a low level console. The low level console is used for kernel printf(9) and ddb(4) debugger support, while the high level console is used by user programs like syslogd(8). Multiple device support is implemented only for the low level console; the high level console is set to the first device in the console list.

Multiple console support may be invoked by passing the kernel the -D flag from the boot loader, or by using conscontrol to change the list of console devices after the system has booted.

The following options are available:
add | delete console
  Add or delete a physical device from the logical console. The device must support low-level console operations. Adding a device will place it at the front of the list of console devices; the first device is used for the high level console.

The console argument is the name of a console device in /dev; the name of the directory may be omitted.

mute on | off
  Change the state of console muting. All console output is suppressed when console muting is on.
set | unset console
  Set or unset the virtual console. When unset, output from the system, such as the kernel printf(9), always goes out to the real main console. When set, it goes to another. This is an interface to the tty ioctl TIOCCONS.


sio(4), syscons(4), tty(4), vt(4), boot(8), loader(8)


The conscontrol utility first appeared in FreeBSD 5.0 .


Jonathan Lemon

CONSCONTROL (8) April 14, 2011

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