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50 lines
1.8 KiB
ReStructuredText
50 lines
1.8 KiB
ReStructuredText
.. _cmd-switch:
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switch - conditionally execute a block of commands
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==================================================
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Synopsis
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--------
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.. synopsis::
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switch VALUE; [case [GLOB ...]; [COMMANDS ...]; ...] end
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Description
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-----------
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``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.
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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.
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Note that fish does not fall through on case statements. Only the first matching case is executed.
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Note that :doc:`break <break>` cannot be used to exit a case/switch block early like in other languages. It can only be used in loops.
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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.
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Example
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-------
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If the variable ``$animal`` contains the name of an animal, the following code would attempt to classify it:
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::
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switch $animal
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case cat
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echo evil
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case wolf dog human moose dolphin whale
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echo mammal
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case duck goose albatross
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echo bird
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case shark trout stingray
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echo fish
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case '*'
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echo I have no idea what a $animal is
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end
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If the above code was run with ``$animal`` set to ``whale``, the output
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would be ``mammal``.
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