ttys.5

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 5 代码 · 共 246 行

.\" SCCSID: @(#)ttys.5	3.1	11/24/87
.TH ttys 5
.SH Name
ttys \- terminal initialization data
.SH Description
.NXR "ttys file" "format"
.NXR "terminal" "initializing"
.NXAM "ttys file" "tset command"
The 
.PN /etc/ttys
file contains information used by various
routines to initialize and control the use of terminal 
special files.  This file is created when the system
is installed and can be updated at any time.
.PP
Each terminal 
special file (
.PN /dev/ttyxx
) has a line in the
.PN ttys
file.  Each line contains 
several fields.  Fields are separated by tabs or spaces.  A field
with more than one word should be enclosed in quotes.  Blank
lines and comments can appear anywhere in the file.  Comments
begin with a number sign (#) and are terminated by a newline character.
Unspecified fields default to the empty string or zero,
as appropriate.
.PP
The format of each line is as follows:
.EX
name command type flag1 flag2 ...
.EE
.IP \fIname\fR 10
Is the name of the special file for the terminal in the 
.PN /dev
directory. Some examples are:
.EX
console
ttyd0
ttyd1
.EE
.IP \fIcommand\fR 10
Is the command to be executed 
each time the terminal is initialized.  This can happen
when the system is booted, or when the superuser adds 
new terminals to the
.PN ttys
file and initializes the new terminals. 
The command is usually
.PN getty ,
which performs such tasks as baud-rate recognition,
reading the login name, and calling
.PN login .
It can be any command you wish, such as the
startup command for a window system terminal emulator or
a command to maintain other daemon processes.
.IP \fItype\fR 10
Is the type of terminal normally connected to the terminal
special file.  You can find the possible types by examining
the 
.PN /etc/termcap
file on your system.  The types available are given as
the third field in
entries in that file.  Some examples are:
.EX
vt100
vt200
dialup
.EE
.IP \fIflags\fR 10
Are the flags to be set in the
.PN ty_status 
or
.PN ty_window
fields of the structure returned by the 
.MS getttyent 3
routine.  If the line ends in a comment, the
comment is included in the
.PN ty_comment
field of this structure.
.IP 
These fields are used by the
.PN init
command that is executed when terminals
are initialized.
.IP
The 
.PN ty_status
flags are:
.RS 10
.IP \f(CWon\fR 10
Sets the TTY_ON bit in the
.PN getttyent
.PN ty_status
field.  This enables logins for this terminal.
.IP 
The default if this flag is not set is that logins
are disabled for the terminal.
.IP \f(CWoff\fR
Clears the TTY_ON bit in the
.PN getttyent 
.PN ty_status
field.  This disables logins for this terminal.
.IP \f(CWsecure\fR
Sets the TTY_SECURE bit in the 
.PN getttyent 
.PN ty_status
field.  This allows the root user to log in on this
terminal.  (The \f(CWon\fR flag should also be set.)
.IP
The default if this flag is not set is that the
root user cannot log in on this terminal.
.IP \f(CWsu\fR
Sets the TTY_SU bit in the 
.PN getttyent
.PN ty_status
field, to allow a user to su to root.
.IP
The default if this flag is not set is that users cannot su to root on
this terminal.
.IP \f(CWnomodem\fR
Sets the TTY_LOCAL bit in the
.PN getttyent 
.PN ty_status
field.  The line ignores modem signals.  This is the
default if neither the \f(CWmodem\fR nor \f(CWnomodem\fR flag
is set.
.IP \f(CWmodem\fR
Clears the TTY_LOCAL bit in the
.PN getttyent 
.PN ty_status
field.  The line recognizes modem signals.
.IP
The default if this flag is not set is \f(CWnomodem\fR.  That is,
the line does not recognize modem signals.
.IP \f(CWshared\fR
Sets the TTY_SHARED bit in the
.PN getttyent 
.PN ty_status
field.  The line can be used for both incoming and
outgoing connections.
.IP
The default if this flag is not set is that the
line cannot be used for incoming and outgoing
connections.
.IP \f(CWtermio\fR
Sets the TTY_TERMIO bit in the 
.PN "getttyent ty_status"
field. This flag causes the terminal line to open with System Five
default termio attributes. If the \f(CWtermio\fR flag is not set, Berkeley
compliant default terminal attributes are used.
.PP
The 
.PN ty_window
flag is:
.IP \f(CWwindow="\fIstring\f(CW"\fR 10
The quoted \fIstring\fR is a window system process
that
.PN init
maintains for the terminal line.
.RE
.SH Examples
.NXR(e) "ttys file" "entries"
The following example permits the root user to log in
on the console at 1200 baud:
.EX
console "/etc/getty std.1200" vt100 on secure
.EE
This example allows dialup at 1200 baud without root
login:
.EX
ttyd0 "/etc/getty d1200" dialup on
.EE
These two examples allow login at 9600 baud with two
different terminal
types:  hp2621-nl and vt100.  In this example, the 
terminals should be set up to operate in 7-bit mode, because
the std.9600 
.PN gettytab
entry is specified:
.EX
tty00 "/etc/getty std.9600" hp2621-nl on
tty01 "/etc/getty std.9600" vt100 on
.EE
This example shows the same two terminals as the previous
example operating in full 8-bit mode.  Note the use of a
different 
.PN gettytab
entry:
.EX
tty00 "/etc/getty 8bit.9600" hp2621-nl on
tty01 "/etc/getty 8bit.9600" vt100 on
.EE
These two examples show network pseudoterminals, which
should not have
.PN getty
enabled:
.EX
ttyp0 none network
ttyp1 none network off
.EE
This example shows a terminal emulator and window-system
startup entry and should be typed all on one line:
.EX
:0 "/usr/bin/login -P /usr/bin/Xprompter -C  /usr/bin/dxsession -e" none
on secure  window="/usr/bin/Xcfb"
.EE
This example shows an example of an entry for an lta device:
.EX
tty01 "/etc/getty 8bit.9600" vt100 on modem secure # LAT
.EE
.NT
Any terminal configured to run 
.PN getty 
in 8-bit mode should specify a
.PN gettytab
entry that declares 8-bit operation.  The command field of the 
.PN ttys 
entry is used to specify the 
.PN gettytab 
entry.  
If the terminal device is set up to operate in 8-bit mode and the command
field does not specify an 8-bit 
.PN gettytab 
entry, output to the terminal
appears as multinational characters.  These characters are the result of
the 
.PN getty 
program using the eighth bit of each character to represent parity
attributes.  By using an 8-bit 
.PN gettytab 
entry, the high order bit of each
character is unaffected by the 
.PN getty 
program.  The examples presented
demonstrate the use of both 7- and 8-bit terminals.
.NE
.SH Files
.TP 15
.PN /etc/ttys
The full pathname for the file
.SH See Also
login(1), getttyent(3), gettytab(5), getty(8), init(8)
.br
\fIGuide to System Environment Setup\fP