Each case command is given one or more parameter. The first case command with a parameter that matches the string specified in the switch command will be evaluated. 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.

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.