gettytab(5)
Name
gettytab − terminal configuration data base
Syntax
/etc/gettytab
Description
The gettytab file is a simplified version of the termcap() data base used to describe terminal lines. The initial terminal login process getty() accesses the 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.
There is a default terminal class, default, that is used to set global defaults for all other classes. That is, the default entry is read, and then the entry for the class required is used to override particular settings.
Capabilities
Refer to termcap() for a description of the file layout. The default column below lists defaults obtained if there is no entry in the table obtained, nor one in the special default table.
| Name | Type | Default | Description |
| ab | bool | false | Auto-baud speed selection mechanism |
| ap | bool | false | Terminal uses any parity |
| bd | num | 0 | Backspace delay |
| bk | str | 0377 | Alternate end of line character (input break) |
| 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 | Ignore garbage characters in login name |
| 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 | Terminal has (or might have) a newline character |
| 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 | Delay between first prompt and following flush (seconds) |
| 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 | Do unbuffered output (of prompts and so forth) |
| 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 |
If no line speed is specified, speed will not be altered from that which prevails when getty is entered. Specifying an input or output speed will override line speed for stated direction only.
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 overriden with one of the f0, f1, or 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.
Should getty receive a null character (presumed to indicate a line break), it will restart using the table indicated by the nx entry. If there is none, it will reuse its original table.
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.
The 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 pc.
The initial message, and login message, im and lm may include the character sequence %h to obtain the host name, %t to obtain the terminal name, and %d to obtain the date. (%% obtains a single percent (%) character.) The host name is normally obtained from the system, but may be set by the hn table entry. In either case, it can be edited with he. The 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 he string causes one character from the real host name to be copied to the final host name. A number sign (#) in the he string causes the next character of the real host name to be skipped. Surplus at signs (@) and number signs (#) are ignored.
When getty executes the login process, given in the lo string (usually /bin/login), it will have set the environment to include the terminal type, as indicated by the tt string, if it exists. The 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 name=value.
If a nonzero timeout is specified with to, then getty will exit within the indicated number of seconds, either having received a login name and passed control to login, or having received an alarm signal, and exited. This may be useful to hang up dial-in lines.
The p8 flag allows use of 8-bit characters.
The pd flag turns off parity on output. Output from getty is even parity unless the op flag, the pd flag, or the p8 flag is specified. The ap flag is used to allow any parity on input. The op(ep) flag may be specified with the 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. getty(8) does not check parity of input characters in RAW mode or 8-bit mode.
Terminals that are set up to operate in 8-bit mode should use gettytab entries which include the p8 flag. If a terminal that is set up in 8-bit mode fails to use an appropriate gettytab entry, the output from getty and login can appear as multinational characters. This is due to the fact that 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.
Restrictions
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 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.
login() destroys the environment, so there is no point setting it in gettytab.