getty.8

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th GETTY VIII 2/11/75
.sh NAME
getty  \*- set typewriter mode
.sh SYNOPSIS
.bd /etc/getty
[ char ]
.sh DESCRIPTION
.it Getty
is invoked
by
.it init
(VIII)
immediately after a typewriter is opened
following a dial-up.
It reads the user's name and invokes the
.it login
command
(I)
with the name as argument.
While reading the name
.it getty
attempts to adapt the system to the speed and type of terminal
being used.
.s3
.it Init
calls
.it getty
with an argument specified by the
.it ttys
file entry for the typewriter line.
Arguments other than `0' can be used to make
.it getty
treat the line specially.
Normally, it
sets the speed of the interface to 300 baud,
specifies that raw mode is to be used (break on every character),
that echo is to be suppressed, and either parity
allowed.
It types the ``login:'' message,
which includes the characters which put the Terminet 300
terminal into full-duplex and
return the GSI terminal to non-graphic mode.
Then the user's name is read, a character at a time.
If a null character is received, it is assumed to be the result
of the user pushing the ``break'' (``interrupt'') key.
The speed is then
changed to 150 baud and the ``login:'' is typed again,
this time including the character
sequence which puts a Teletype 37
into full-duplex.
If a subsequent null character is received,
the speed is changed back to 300 baud.
.s3
The user's name is terminated by a new-line or
carriage-return character.
The latter results in the system being set to
treat carriage returns appropriately (see
.it stty
(II)).
.s3
The user's name is scanned to see if
it contains any lower-case alphabetic characters; if not,
and if the name is nonempty, the
system is told to map any future upper-case characters
into the corresponding lower-case characters.
.s3
Finally, login is called with the user's name as argument.
.sh "SEE ALSO"
init (VIII), login (I), stty (II), ttys (V)
.sh BUGS