#!/usr/bin/perl --
use strict;
use warnings;
use POSIX qw/ strftime mktime /;
Main( @ARGV );
exit( 0 );
sub Main {
    ...    
    if( FileUpdatedToday( $filename ) ){
        print "\ file has already been updated today";
    } else {
        UpdateFile( $filename );
    }
    if( not -s $temp ){
        EmailReport( $temp );
    }
}
sub EmailReport {
    my( $temp ) = @_;
    exec $^X, $emailPL, or die "problem with $emailPL";
}
sub FileUpdatedToday {
    ...
    return !!1;
    ..
    return !!0;
}
sub UpdateFile {
    ...
}