tty(1)							      General Commands Manual							    tty(1)

NAME

       tty - Returns pathname of terminal device

SYNOPSIS

       tty [-s]

       The  tty  command  writes  the  full pathname of your terminal device to standard output.  The tty command may also be used to determine if
       standard input is a terminal.

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       tty:  XCU5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

OPTIONS

       Suppresses reporting the pathname.

       The XCU specification states that -s option is obsolete and recommends the portable applications use test -t 0 instead of tty -s.

OPERANDS

       None

DESCRIPTION

       The command tty -s evaluates as TRUE if standard input is a display and FALSE if it is not.

       [Tru64 UNIX]  The file /dev/tty is a special file always refers to your controlling terminal, although it also may have another	name  like
       /dev/console  or /dev/tty2.  To avoid writing undesirable output to an output file--for example, to write a prompt in a shell script to the
       screen, while writing the response to the prompt to an output file--redirect standard output to /dev/tty.

NOTES

       While the -s option is useful if only the exit code is wanted, it does not rely on any ability to form a valid  pathname.  For  a  portable
       application you should use the command test -t 0.

EXIT STATUS

       The  following exit values are returned: Successful completion.	Standard input is not a display.  [Tru64 UNIX]	Invalid options specified.
       [Tru64 UNIX]  An error occurred.

DIAGNOSTICS

       [Tru64 UNIX]  Your standard input is not a display and you did not specify the -s option.

EXAMPLES

       To display full pathname of your terminal device, enter: tty To test whether or not the standard input is a terminal device, create a shell
       script containing the following: if tty -s then	    echo 'Output is a display' else	 echo 'Output is not a display' fi

	      If  the  standard input is a terminal device, this displays the Output is a display message. If the standard input is not a terminal
	      device, it displays the Output is not a display message.

ENVIRONMENT VARIABLES

       The following environment variables affect the execution of tty: Provides a default value for the internationalization variables  that  are
       unset or null. If LANG is unset or null, the corresponding value from the default locale is used.  If any of the internationalization vari-
       ables contain an invalid setting, the utility behaves as if none of the variables had been defined.  If set to a  non-empty  string  value,
       overrides  the  values of all the other internationalization variables.	Determines the locale for the interpretation of sequences of bytes
       of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).  Determines the locale for the  for-
       mat  and  contents  of  diagnostic messages written to standard error.  Determines the location of message catalogues for the processing of
       LC_MESSAGES.

FILES

       Pseudodevice representing the user's controlling terminal.

SEE ALSO

       Commands:  stty(1), test(1)

       Routines:  ttyname(3)

       Files:  tty(7)

       Standards:  standards(5)

																	    tty(1)