<div>
perldoc -f require<br />
&nbsp; &nbsp; require EXPR<br />
&nbsp; &nbsp; require Demands some semantics specified by EXPR, or by `$_' if EXPR<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; is not supplied. If EXPR is numeric, demands that the<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; current version of Perl (`$]' or $PERL_VERSION) be equal<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; or greater than EXPR.<br />
<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Otherwise, demands that a library file be included if it<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; hasn't already been included. The file is included via<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; the do-FILE mechanism, which is essentially just a<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; variety of `eval()'. Has semantics similar to the<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; following subroutine:<br />

</div>


perldoc -f require
    require EXPR
    require Demands some semantics specified by EXPR, or by `$_' if EXPR
            is not supplied. If EXPR is numeric, demands that the
            current version of Perl (`$]' or $PERL_VERSION) be equal
            or greater than EXPR.

            Otherwise, demands that a library file be included if it
            hasn't already been included. The file is included via
            the do-FILE mechanism, which is essentially just a
            variety of `eval()'. Has semantics similar to the
            following subroutine:


<div>
<div class="content wysiwyg-content">
require &quot;auth.conf&quot;;<br />
require 5; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; what is 5 and how does it use ?<br />
<br />
<br />

</div>
</div>


require "auth.conf";
require 5;                         what is 5 and how does it use ?




What os that ?

Perl is a high-level, general-purpose, interpreted, dynamic programming languages with over 25 years of development. Perl 5 runs on over 100 platforms from portables to mainframes and is suitable for both rapid prototyping and large-scale development projects.  Perl gained widespread popularity as a Common Gateway Interface (CGI) scripting language, in part due to its regular expression and string parsing abilities. In addition to CGI, Perl is used for graphics programming, system administration, network programming, finance, bioinformatics, and other applications.