package MyAppCommon;
use strict;

sub CommonPageStart {
  ...
}

sub CommonPageEnd {
  ...
}

1;
__END__

# and then, in your scripts
use MyAppCommon;  # use is basically like require... see the docs for details
MyAppCommon::CommonPageStart(...);

# your stuff

MyAppCommon::CommonPageEnd(...);

##</code><code>##

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