in reply to Find most frequently used word in text file.

Try this alternative code, and let us know if you need help understanding it. Please indicate exactly what part you need help with : 
perl -anE "for (@F){s/\W//g;$_ or next; $h{$_}++}}{$k=(sort {$h{$a} <=
+> $h{$b}} keys %h)[-1]; say qq|The most frequent word in $ARGV is $k,
+ which was seen $h{$k} times.|" **YOUR-FILE-NAME**

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(Use single quotes, if run on linux).

             When in doubt, mumble; when in trouble, delegate; when in charge, ponder. -- James H. Boren

In Section Seekers of Perl Wisdom