phpMan > info > tty(4)

File: coreutils.info,  Node: tty invocation,  Prev: printenv invocation,  Up: Working context

19.4 'tty': Print file name of terminal on standard input

'tty' prints the file name of the terminal connected to its standard
input.  It prints 'not a tty' if standard input is not a terminal.
Synopsis:

     tty [OPTION]...

   The program accepts the following option.  Also see *note Common
options::.

'-s'
'--silent'
'--quiet'
     Print nothing; only return an exit status.

   Exit status:

     0 if standard input is a terminal
     1 if standard input is a non-terminal file
     2 if given incorrect arguments
     3 if a write error occurs