TTY

tty ? controlling terminal

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 synonym 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.

/dev/tty

mknod(1), chown(1), getty(1), termios(2), console(4), ttys(4)