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Alphabetical listing for T

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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
  -s  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  The XCU specification states that -s option is obsolete and recommends the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:

  0   Successful completion.

  1   Standard input is not a display.

  2   [Tru64 UNIX]  Invalid options specified.

  >2  [Tru64 UNIX]  An error occurred.

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

EXAMPLES
   1.  To display full pathname of your terminal device, enter:
	    tty

   2.  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:

  LANG
      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
      variables contain an invalid setting, the utility behaves as if none of
      the variables had been defined.

  LC_ALL
      If set to a non-empty string value, overrides the values of all the
      other internationalization variables.

  LC_CTYPE
      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).

  LC_MESSAGES
      Determines the locale for the format and contents of diagnostic
      messages written to standard error.

  NLSPATH
      Determines the location of message catalogues for the processing of
      LC_MESSAGES.

FILES
  /dev/tty
      Pseudodevice representing the user's controlling terminal.

SEE ALSO
  Commands:  stty(1), test(1)

  Routines:  ttyname(3)

  Files:  tty(7)

  Standards:  standards(5)

Index for Section 1

Alphabetical listing for T

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