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ISATTY(1)			  fish-shell			     ISATTY(1)

NAME
       isatty -	test if	a file descriptor is a terminal

SYNOPSIS
	  isatty [FILE DESCRIPTOR]

DESCRIPTION
       isatty tests if a file descriptor is a terminal (as opposed to a	file).
       The name	is derived from	the system call	of the same  name,  which  for
       historical reasons refers to a teletypewriter (TTY).

       FILE  DESCRIPTOR	 may be	either the number of a file descriptor,	or one
       of the strings stdin, stdout, or	stderr.	If not specified, zero is  as-
       sumed.

       If  the specified file descriptor is a terminal device, the exit	status
       of the command is zero. Otherwise, the exit status is non-zero. No mes-
       sages are printed to standard error.

EXAMPLES
       From  an	interactive shell, the commands	below exit with	a return value
       of zero:

	  isatty
	  isatty stdout
	  isatty 2
	  echo | isatty	1

       And these will exit non-zero:

	  echo | isatty
	  isatty 9
	  isatty stdout	> file
	  isatty 2 2> file

COPYRIGHT
       2021, fish-shell	developers

3.3				 Apr 04, 2022			     ISATTY(1)
NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | COPYRIGHT

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