fish-shell/doc_src/cmds/while.rst

.. _cmd-while:

while - perform a command multiple times
========================================

Synopsis
--------

::

    while CONDITION; COMMANDS...; end


Description
-----------

``while`` repeatedly executes ``CONDITION``, and if the exit status is 0, then executes ``COMMANDS``.

The exit status of the while loop is the exit status of the last iteration of the ``COMMANDS`` executed, or 0 if none were executed. (This matches other shells and is POSIX-compatible.)

You can use :ref:`and <cmd-and>` or :ref:`or <cmd-or>` for complex conditions. Even more complex control can be achieved with ``while true`` containing a :ref:`break <cmd-break>`.

Example
-------


::

    while test -f foo.txt; or test -f bar.txt ; echo file exists; sleep 10; end
    # outputs 'file exists' at 10 second intervals as long as the file foo.txt or bar.txt exists.
docs: Add labels to all commands This allows us to use :ref: references, which don't require hardcoding it as html [ci skip] 2019-03-31 17:05:09 +08:00			`.. _cmd-while:`

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			`--------`
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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			`::`

			`while CONDITION; COMMANDS...; end`
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Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			``while`` repeatedly executes ``CONDITION``, and if the exit status is 0, then executes ``COMMANDS``.
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Incorporate most new doc changes since branch Adds most documentation changes since 72c0213d42b77b2f01223b5515669840110ea9b9 2019-02-25 07:01:16 +08:00			The exit status of the while loop is the exit status of the last iteration of the ``COMMANDS`` executed, or 0 if none were executed. (This matches other shells and is POSIX-compatible.)
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
docs: Use more command labels 2019-03-31 17:24:04 +08:00			You can use :ref:`and <cmd-and>` or :ref:`or <cmd-or>` for complex conditions. Even more complex control can be achieved with ``while true`` containing a :ref:`break <cmd-break>`.
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			`::`

			`while test -f foo.txt; or test -f bar.txt ; echo file exists; sleep 10; end`
			`# outputs 'file exists' at 10 second intervals as long as the file foo.txt or bar.txt exists.`