TTY(4) Linux Programmer's Manual TTY(4)
NAME
tty - controlling terminal
DESCRIPTION
The file /dev/tty is a character file with major number 5 and minor number 0, usually of mode 0666 and owner.group root.tty. It is a syn-
onym for the controlling terminal of a process, if any.
In addition to the ioctl() requests supported by the device that tty refers to, the following ioctl() request is supported:
TIOCNOTTY
Detach the current process from its controlling terminal, and remove it from its current process group, without attaching it to a
new process group (that is, set its process group ID to zero). This ioctl() call only works on file descriptors connected to
/dev/tty; this is used by daemon processes when they are invoked by a user at a terminal. The process attempts to open /dev/tty; if
the open succeeds, it detaches itself from the terminal by using TIOCNOTTY, while if the open fails, it is obviously not attached to
a terminal and does not need to detach itself.
FILES
/dev/tty
SEE ALSO
mknod(1), chown(1), getty(1), termios(3), console(4), ttys(4)
Linux 1992-01-21 TTY(4)
