fish-shell/sphinx_doc_src/cmds/isatty.rst
David Adam 02d82dcf85 docs: update all command synopsis formatting
Adds synopses for those commands missing them.

Moves all synopsis sections to code blocks. This improves the appearance, although highlighting as
fish code may not be the ideal appearance.
2019-09-17 17:59:04 +08:00

49 lines
816 B
ReStructuredText

.. _cmd-isatty:
isatty - test if a file descriptor is a tty.
============================================
Synopsis
--------
::
isatty [FILE DESCRIPTOR]
Description
-----------
``isatty`` tests if a file descriptor is a tty.
``FILE DESCRIPTOR`` may be either the number of a file descriptor, or one of the strings ``stdin``, ``stdout``, or ``stderr``.
If the specified file descriptor is a tty, the exit status of the command is zero. Otherwise, the exit status is non-zero. No messages 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