mirror of https://github.com/mkerrisk/man-pages
85 lines
2.4 KiB
Groff
85 lines
2.4 KiB
Groff
.\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
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.\" Fri Apr 2 11:32:09 MET DST 1993
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, see
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.\" <http://www.gnu.org/licenses/>.
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.\" %%%LICENSE_END
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.\"
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.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
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.\" Modified 2003-04-07 by Michael Kerrisk
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.\"
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.TH TTY 4 2003-04-07 "Linux" "Linux Programmer's Manual"
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.SH NAME
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tty \- controlling terminal
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.SH DESCRIPTION
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The file
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.I /dev/tty
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is a character file with major number 5 and
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minor number 0, usually of mode 0666 and owner.group root.tty.
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It is a synonym for the controlling terminal of a process, if any.
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.LP
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In addition to the
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.BR ioctl (2)
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requests supported by the device that
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.B tty
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refers to, the
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.BR ioctl (2)
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request
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.B TIOCNOTTY
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is supported.
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.SS TIOCNOTTY
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Detach the calling process from its controlling terminal.
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.sp
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If the process is the session leader,
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then
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.B SIGHUP
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and
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.B SIGCONT
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signals are sent to the foreground process group
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and all processes in the current session lose their controlling tty.
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.sp
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This
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.BR ioctl (2)
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call works only on file descriptors connected
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to
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.IR /dev/tty .
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It is used by daemon processes when they are invoked
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by a user at a terminal.
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The process attempts to open
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.IR /dev/tty .
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If the open succeeds, it
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detaches itself from the terminal by using
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.BR TIOCNOTTY ,
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while if the
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open fails, it is obviously not attached to a terminal and does not need
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to detach itself.
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.SH FILES
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/dev/tty
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.SH SEE ALSO
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.BR chown (1),
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.BR mknod (1),
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.BR ioctl (2),
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.BR termios (3),
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.BR console_ioctl (4),
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.BR tty_ioctl (4),
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.BR ttyS (4),
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.BR agetty (8),
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.BR mingetty (8)
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