There's no switch statement. You can't take the address of anything. Signal handlers deal with signal names, not numbers. The backtick operator does no translation of the return value, unlike csh . Perl does substitution only in certain constructs such as double quotes, backticks, angle brackets and search patterns.
Shells interpret scripts a little bit at a time.
Perl compiles the whole program before executing it. The environment is not automatically made available as variables. Go to the first , previous , next , last section, table of contents .