fish-shell/doc_src/cmds/switch.rst

.. _cmd-switch:

switch - conditionally execute a block of commands
==================================================

Synopsis
--------

**switch** *VALUE*; [**case** [*GLOB*...]; [*COMMANDS*...]; ...] **end**

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

``switch`` performs one of several blocks of commands, depending on whether a specified value equals one of several globbed values. ``case`` is used together with the ``switch`` statement in order to determine which block should be executed.

Each ``case`` command is given one or more parameters. The first ``case`` command with a parameter that matches the string specified in the switch command will be evaluated. ``case`` parameters may contain globs. These need to be escaped or quoted in order to avoid regular glob expansion using filenames.

Note that fish does not fall through on case statements. Only the first matching case is executed.

Note that command substitutions in a case statement will be evaluated even if its body is not taken. All substitutions, including command substitutions, must be performed before the value can be compared against the parameter.


Example
-------

If the variable \$animal contains the name of an animal, the following code would attempt to classify it:


::

    switch $animal
        case cat
            echo evil
        case wolf dog human moose dolphin whale
            echo mammal
        case duck goose albatross
            echo bird
        case shark trout stingray
            echo fish
        case '*'
            echo I have no idea what a $animal is
    end


If the above code was run with ``$animal`` set to ``whale``, the output
would be ``mammal``.
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-switch:`

Switch command docs from \section to reStructuredText 2018-12-17 09:39:33 +08:00			`switch - conditionally execute a block of commands`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`==================================================`
Switch command docs from \section to reStructuredText 2018-12-17 09:39:33 +08:00
Migrate the 'synopsis' sections to .rst format 2018-12-18 09:58:24 +08:00			`Synopsis`
			`--------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
More synopsis work. A great leap forward 2021-12-22 09:24:47 +08:00			`switch VALUE; [case [GLOB...]; [COMMANDS...]; ...] end`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Convert \\subsection sections into rst format 2018-12-19 10:44:30 +08:00			`Description`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`-----------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
More synopsis work. A great leap forward 2021-12-22 09:24:47 +08:00			``switch`` performs one of several blocks of commands, depending on whether a specified value equals one of several globbed values. ``case`` is used together with the ``switch`` statement in order to determine which block should be executed.
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
More synopsis work. A great leap forward 2021-12-22 09:24:47 +08:00			Each ``case`` command is given one or more parameters. The first ``case`` command with a parameter that matches the string specified in the switch command will be evaluated. ``case`` parameters may contain globs. These need to be escaped or quoted in order to avoid regular glob expansion using filenames.
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
			`Note that fish does not fall through on case statements. Only the first matching case is executed.`

			`Note that command substitutions in a case statement will be evaluated even if its body is not taken. All substitutions, including command substitutions, must be performed before the value can be compared against the parameter.`


Convert \\subsection sections into rst format 2018-12-19 10:44:30 +08:00			`Example`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`-------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
			`If the variable \$animal contains the name of an animal, the following code would attempt to classify it:`

Switch \fish sections to rst format 2018-12-19 11:14:04 +08:00

			`::`

			`switch $animal`
			`case cat`
			`echo evil`
			`case wolf dog human moose dolphin whale`
			`echo mammal`
			`case duck goose albatross`
			`echo bird`
			`case shark trout stingray`
			`echo fish`
			`case '*'`
			`echo I have no idea what a $animal is`
			`end`

Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			If the above code was run with ``$animal`` set to ``whale``, the output
			would be ``mammal``.