FAQ 8.46: What's the difference between require and use?

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8.46: What's the difference between require and use?

    Perl offers several different ways to include code from one file into
    another. Here are the deltas between the various inclusion constructs:

        1)  do $file is like eval `cat $file`, except the former
            1.1: searches @INC and updates %INC.
            1.2: bequeaths an *unrelated* lexical scope on the eval'ed code.

        2)  require $file is like do $file, except the former
            2.1: checks for redundant loading, skipping already loaded files.
            2.2: raises an exception on failure to find, compile, or execute

        3)  require Module is like require "Module.pm", except the former
            3.1: translates each "::" into your system's directory separator.
            3.2: primes the parser to disambiguate class Module as an indirect

        4)  use Module is like require Module, except the former
            4.1: loads the module at compile time, not run-time.
            4.2: imports symbols and semantics from that package to the current

    In general, you usually want "use" and a proper Perl module.


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