gettytab.5

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 5 代码 · 共 301 行

.\" SCCSID: @(#)gettytab.5	3.2	2/8/88
.TH gettytab 5
.SH Name
gettytab \- terminal configuration data base
.SH Syntax
/etc/gettytab
.SH Description
.NXB "gettytab file" "format"
.NXR "terminal" "setting characteristics"
.NXAM "getty program" "gettytab file"
.NXA "termcap file" "gettytab file"
The
.PN gettytab
file
is a simplified version of the 
.MS termcap 5
data base
used to describe terminal lines.
The initial terminal login process 
.MS getty 8
accesses the
.PN gettytab
file each time it starts, allowing simpler
reconfiguration of terminal characteristics.
Each entry in the data base
is used to describe one class of terminal.
.PP
There is a default terminal class,
.IR default ,
that is used to set global defaults for all other classes.
That is, the
.I default 
entry is read, and then the entry for the class required
is used to override particular settings.
.SH Capabilities
Refer to 
.MS termcap 5
for a description of the file layout.
The
.I default
column below lists defaults obtained if there is
no entry in the table obtained, nor one in the special
.I default
table.
.NXR "gettytab file" "defaults"
.PP
.TS
tab(@);
lfHB lfHB lfHB lfHB
lfR  lfR  lfR   lfR .
_
.sp 4p
Name@Type@Default@Description
.sp 4p
_
.sp 6p
ab@bool@false@Auto-baud speed selection mechanism
ap@bool@false@Terminal uses any parity
bd@num@0@Backspace delay
bk@str@0377@T{
Alternate end of line character (input break)
T}
cb@bool@false@Use crt backspace mode
cd@num@0@Carriage-return delay
ce@bool@false@Use crt erase algorithm
ck@bool@false@Use crt kill algorithm
cl@str@NULL@Screen clear sequence
co@bool@false@Console \- add \\n after login prompt
ds@str@^Y@Delayed suspend character
ec@bool@false@Leave echo 2OFF
ep@bool@false@Terminal uses even parity
er@str@^?@Erase character
et@str@^D@End of text 2EOF character
ev@str@NULL@Initial environment
f0@num@unused@Tty mode flags to write messages
f1@num@unused@Tty mode flags to read login name
f2@num@unused@Tty mode flags to leave terminal as
fd@num@0@Form-feed (vertical motion) delay
fl@str@^O@Output flush character
hc@bool@false@Do not hangup line on last close
he@str@NULL@Hostname editing string
hn@str@hostname@Hostname
ht@bool@false@Terminal has real tabs
ig@bool@false@T{
Ignore garbage characters in login name
T}
im@str@NULL@Initial (banner) message
in@str@^C@Interrupt character
is@num@unused@Input speed
kl@str@^U@Kill character
lc@bool@false@Terminal has lower case
lm@str@login:@Login prompt
ln@str@^V@``literal next'' character
lo@str@/bin/login@Program to exec when name obtained
nd@num@0@Newline (line-feed) delay
nl@bool@false@T{
Terminal has (or might have) a newline character
T}
nx@str@default@Next table (for auto speed selection)
op@bool@false@Terminal uses odd parity
os@num@unused@Output speed
p8@bool@false@Use 8-bit characters
pc@str@\\0@Pad character
pd@bool@false@Disable parity on output
pe@bool@false@Use printer (hard copy) erase algorithm
pf@num@0@T{
Delay between first prompt and following flush (seconds)
T}
ps@bool@false@Line connected to a MICOM port selector
qu@str@^\\@Quit character
rp@str@^R@Line retype character
rw@bool@false@Do not use raw for input, use cbreak
sp@num@unused@Line speed (input and output)
su@str@^Z@Suspend character
tc@str@none@Table continuation
to@num@0@Timeout (seconds)
tt@str@NULL@Terminal type (for environment)
ub@bool@false@T{
Do unbuffered output (of prompts and so forth)
T}
uc@bool@false@Terminal is known upper-case only
we@str@^W@Word erase character
xc@bool@false@Do not echo control chars as ^X
xf@str@^S@XOFF (stop output) character
xn@str@^Q@XON (start output) character
.sp 6p
_
.TE
.PP
If no line speed is specified, speed will not be altered
from that which prevails when 
.PN getty 
is entered.
Specifying an input or output speed will override
line speed for stated direction only.
.PP
Terminal modes to be used for the output of the message,
for input of the login name,
and to leave the terminal set as upon completion,
are derived from the Boolean flags specified.
If the derivation should prove inadequate,
any (or all) of these three may be overridden
with one of the
.PN f0 ,
.PN f1 ,
or
.PN f2
numeric specifications, which can be used to specify
(usually in octal, with a leading 0)
the exact values of the flags.
Local (new tty) flags are set in the top 16 bits
of this (32-bit) value.
.PP
Should
.PN getty
receive a null character
(presumed to indicate a line break), 
it will restart using the table indicated by the
.PN nx
entry. If there is none, it will reuse its original table.
.PP
Delays are specified in milliseconds; the nearest possible
delay available in the tty driver will be used.
Should greater certainty be desired, delays
with values 0, 1, 2, and 3 are interpreted as
choosing that particular delay algorithm from the driver.
.PP
The
.PN cl
screen clear string may be preceded by a (decimal) number
of milliseconds of delay required (a la termcap).
This delay is simulated by repeated use of the pad character
.PN pc .
.PP
The initial message, and login message,
.PN im
and
.PN lm
may include the character sequence
.PN %h
to obtain the host name, 
.PN %t
to obtain the terminal name, and 
.PN %d
to obtain the date.
(\fB%%\fP obtains a single percent (%) character.)
The host name is normally obtained from the system,
but may be set by the
.PN hn
table entry.
In either case, it can be edited with
.PN he .
The
.PN he
string is a sequence of characters; each character that is neither an 
at sign (@) nor a number sign (#) is copied into the final host name.
An at sign (@) in the
.PN he
string causes one character from the real host name to
be copied to the final host name.
A number sign (#) in the
.PN he
string causes the next character of the real host name
to be skipped.
Surplus at signs (@) and number signs (#) are ignored.
.PP
When 
.PN getty
executes the login process, given in the
.PN lo
string (usually 
.PN /bin/login) , 
it will have set
the environment to include the terminal type, as indicated by the
.PN tt
string, if it exists.
The
.PN ev
string can be used to enter additional data into the environment.
It is a list of comma-separated strings, each of which
should be of the form
.IR name=value .
.PP
If a nonzero timeout is specified with
.PN to ,
then 
.PN getty
will exit within the indicated
number of seconds, either having
received a login name and passed control
to
.PN login ,
or having received an alarm signal, and exited.
This may be useful to hang up dial-in lines.
.PP
The
.PN p8
flag allows use of 8-bit characters.
.PP
The
.PN pd
flag turns off parity on output.  Output from
.PN getty
is even parity unless the
.PN op
flag, the
.PN pd
flag, or the
.PN p8
flag is specified.  The
.PN ap
flag is used to allow any parity on input.
The
.PN op(ep)
flag may be specified with the
.PN ap
flag to allow any parity on input, but generate odd(even)
parity on output.
The parity on output is accomplished by
using the eighth bit as the parity bit.
.PN getty(8)
does not check parity of input characters in RAW mode
or 8-bit mode.
.PP
Terminals that are set up to operate in 8-bit mode should use
.PN gettytab 
entries which include the 
.PN p8 
flag.  If a terminal that is set up
in 8-bit mode fails to use an appropriate 
.PN gettytab 
entry, the output from
.PN getty
and
.PN login
can appear as multinational characters.  This is due to the fact that
.PN getty
uses the eighth bit of characters to provide software generated parity.
The software parity generation will transform certain ASCII characters
into multinational characters.  Earlier releases of the ULTRIX operating
system did not display these multinational characters, due to the lack of
full 8-bit support in the terminal subsystem.
.SH Restrictions
.NXR "gettytab file" "restricted"
Because some users insist on changing their default special
characters, it is wise to define at least the 
erase, kill, and interrupt characters in the
.B default
table.
In all
cases, # or CTRL/H typed in a login name will be treated as
an erase character, and @ will be treated as a kill character.
.PP
.MS login 1
destroys the environment, so there is no point
setting it in
.PN gettytab .
.SH See Also
termcap(5), getty(8)
.NXE "gettytab file" "format"