To match arbitrary words use \w+ instead of "perlmonk":

    #!/usr/bin/perl -wl

    use strict;

    my $line1  = "perlmonk perlmonk perlmonk";
    my $count1 = () = $line1 =~ /perlmonk/g;

    my $line2  = "perl m onk p erlmonk per lm onk";
       # Remove the spaces and count as before
       $line2  =~ s/ //g;
    my $count2 = () = $line2 =~ /perlmonk/g;

    print for $count1, $count2;

    __END__
    Prints:

    3
    3
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--
John.