tty(4) — Linux manual page

tty(4)                  Kernel Interfaces 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 with mode 0666 and ownership root:tty.
       It is a synonym for the controlling terminal of a process, if
       any.

       In addition to the ioctl(2) requests supported by the device that
       tty refers to, the ioctl(2) request TIOCNOTTY is supported.

   TIOCNOTTY
       Detach the calling process from its controlling terminal.

       If the process is the session leader, then SIGHUP and SIGCONT
       signals are sent to the foreground process group and all
       processes in the current session lose their controlling tty.

       This ioctl(2) call works only on file descriptors connected to
       /dev/tty.  It 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

       chown(1), mknod(1), ioctl(2), ioctl_console(2), ioctl_tty(2),
       termios(3), ttyS(4), vcs(4), pty(7), agetty(8), mingetty(8)

COLOPHON

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-05-02                         tty(4)

Pages that refer to this page: screen(1), setterm(1), tset(1), ioctl(2), ioctl_console(2), open(2), stdin(3), ttyS(4), vcs(4), pty(7), termio(7), pam_selinux(8)

---