fish-shell/doc_src/case.txt
axel a7f977836a Expand the switch/case documentation
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2006-04-21 18:35:29 +10:00

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\section case case - conditionally execute a block of commands
\subsection case-synopsis Synopsis
<tt>switch VALUE; [case [WILDCARD...]; [COMMANDS...];...] end</tt>
\subsection case-description Description
The \c switch statement is used to perform one of several blocks of
commands depending on whether a specified value equals one of several
wildcarded values. The \c case statement is used together with the \c
switch statement in order to determine which block should be
performed.
Each \c case command is given one or more parameter. The first \c case
command with a parameter that matches the string specified in the
switch command will be evaluated. \c case parameters may contain
wildcards. These need to be escaped or quoted in order to avoid
regular wildcard expansion using filenames.
Note that fish does not fall through on case statements. Though the
syntax may look a bit like C switch statements, it behaves more like
the case stamantes of traditional shells.
Also note that command substitutions in a case statement will be
evaluated even if it's body is not taken. This may seem
counterintuitive at first, but it is unavoidable, since it would be
impossible to know if a case command will evaluate to true before all
forms of parameter expansion have been performed for the case command.
\subsection case-example Example
If the variable \$animal contains the name of an animal, the following
code would attempt to classify it:
<p>
<pre>
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
</pre>
</p>
<p>
If the above code was run with \c \$animal set to \c whale, the output would be \c mammal.
</p>