2004-11-03 13:51:07 +00:00
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\" This man page was written by Jeremy Phelps <jphelps@notreached.net>.
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.\" Notes added - aeb
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.\" Redistribute and revise at will.
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.\"
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2007-05-18 09:11:21 +00:00
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.TH PTS 4 2002-10-09 "Linux" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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ptmx, pts \- psuedoterminal master and slave
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.SH DESCRIPTION
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2005-11-02 13:55:25 +00:00
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The file \fI/dev/ptmx\fP is a character file with major number 5 and
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minor number 2, usually of mode 0666 and owner.group of root.root.
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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It is used to create a psuedoterminal master and slave pair.
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2004-11-03 13:51:07 +00:00
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.PP
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2005-11-02 13:55:25 +00:00
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When a process opens \fI/dev/ptmx\fP, it gets a file
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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descriptor for a psuedoterminal master (PTM),
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and a psuedoterminal slave (PTS) device is created in the
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.I /dev/pts
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directory.
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Each file descriptor obtained by opening \fI/dev/ptmx\fP
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is an independent PTM with its own associated PTS, whose path can
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be found by passing the descriptor to
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.BR ptsname (3).
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.PP
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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Before opening the psuedoterminal slave, you must pass the master's file
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2004-11-03 13:51:07 +00:00
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descriptor to
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.BR grantpt (3)
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and
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.BR unlockpt (3).
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.PP
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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Once both the psuedoterminal master and slave are open, the slave provides
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2004-11-03 13:51:07 +00:00
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processes with an interface that is identical to that of a real terminal.
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.PP
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Data written to the slave is presented on the master descriptor as input.
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Data written to the master is presented to the slave as input.
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.PP
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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In practice, psuedoterminals are used for implementing terminal emulators
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such as
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.BR xterm (1),
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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in which data read from the psuedoterminal master is interpreted by the
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2004-11-03 13:51:07 +00:00
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application in the same way
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a real terminal would interpret the data, and for implementing remote-login
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programs such as
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.BR sshd (8),
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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in which data read from the psuedoterminal master is sent across the network
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to a client program that is connected to a terminal or terminal emulator.
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.PP
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open.2, poll.2, select_tut.2, getpt.3, grantpt.3, openpty.3, posix_openpt.3, ptsname.3, unlockpt.3, pts.4, tty_ioctl.4, proc.5, pty.7: Global fix: s/pseudo-terminal/pseudoterminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-12 04:51:51 +00:00
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Psuedoterminals can also be used to send input to programs that normally
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refuse to read input from pipes (such as
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2007-10-14 18:33:54 +00:00
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.BR su (1),
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and
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2007-10-14 18:33:54 +00:00
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.BR passwd (1)).
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.SH FILES
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.IR /dev/ptmx ,
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.I /dev/pts/*
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.SH NOTES
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2010-10-12 04:55:18 +00:00
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The Linux support for the above (known as UNIX 98 psuedoterminal naming)
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is done using the
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.I devpts
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2008-03-19 07:26:08 +00:00
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file system, that should be mounted on
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.IR /dev/pts .
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.LP
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2010-10-12 04:55:18 +00:00
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Before this UNIX 98 scheme, master psuedoterminals were called
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2004-11-03 13:51:07 +00:00
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.IR /dev/ptyp0 ", ..."
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2010-10-12 04:55:18 +00:00
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and slave psuedoterminals
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.IR /dev/ttyp0 ", ..."
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and one needed lots of preallocated device nodes.
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.SH "SEE ALSO"
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.BR getpt (3),
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.BR grantpt (3),
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.BR ptsname (3),
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2005-10-10 13:14:12 +00:00
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.BR unlockpt (3),
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.BR pty (7)
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