I'm not sure why everyone wants to use split when you really just want one of the parts.

$_ = "foo::bar";

my ($head) = /^.*?::/;
my ($tail) = /::.*/;
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That said, if you need them both of them at various times, you should probably split on :: to an array when you read the file and then pass a reference to that around.

Makeshifts last the longest.