Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

console(4) [centos man page]

CONSOLE(4)						     Linux Programmer's Manual							CONSOLE(4)

NAME
console - console terminal and virtual consoles DESCRIPTION
A Linux system has up to 63 virtual consoles (character devices with major number 4 and minor number 1 to 63), usually called /dev/ttyn with 1 <= n <= 63. The current console is also addressed by /dev/console or /dev/tty0, the character device with major number 4 and minor number 0. The device files /dev/* are usually created using the script MAKEDEV, or using mknod(1), usually with mode 0622 and owner root.tty. Before kernel version 1.1.54 the number of virtual consoles was compiled into the kernel (in tty.h: #define NR_CONSOLES 8) and could be changed by editing and recompiling. Since version 1.1.54 virtual consoles are created on the fly, as soon as they are needed. Common ways to start a process on a console are: (a) tell init(8) (in inittab(5)) to start a mingetty(8) (or agetty(8)) on the console; (b) ask openvt(1) to start a process on the console; (c) start X--it will find the first unused console, and display its output there. (There is also the ancient doshell(8).) Common ways to switch consoles are: (a) use Alt+Fn or Ctrl+Alt+Fn to switch to console n; AltGr+Fn might bring you to console n+12 [here Alt and AltGr refer to the left and right Alt keys, respectively]; (b) use Alt+RightArrow or Alt+LeftArrow to cycle through the presently allocated consoles; (c) use the program chvt(1). (The key mapping is user settable, see loadkeys(1); the above mentioned key combinations are according to the default settings.) The command deallocvt(1) (formerly disalloc) will free the memory taken by the screen buffers for consoles that no longer have any associ- ated process. Properties Consoles carry a lot of state. I hope to document that some other time. The most important fact is that the consoles simulate vt100 ter- minals. In particular, a console is reset to the initial state by printing the two characters ESC c. All escape sequences can be found in console_codes(4). FILES
/dev/console /dev/tty* SEE ALSO
chvt(1), deallocvt(1), loadkeys(1), mknod(1), openvt(1), console_codes(4), console_ioctl(4), tty(4), ttyS(4), charsets(7), agetty(8), init(8), mapscrn(8), mingetty(8), resizecons(8), setfont(8) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 1994-10-31 CONSOLE(4)

Check Out this Related Man Page

CONSCONTROL(8)						    BSD System Manager's Manual 					    CONSCONTROL(8)

NAME
conscontrol -- control physical console devices SYNOPSIS
conscontrol [list] conscontrol mute on | off conscontrol add | delete console conscontrol set | unset console DESCRIPTION
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. SEE ALSO
sio(4), syscons(4), tty(4), vt(4), boot(8), loader(8) HISTORY
The conscontrol utility first appeared in FreeBSD 5.0. AUTHORS
Jonathan Lemon BSD
April 14, 2011 BSD
Man Page