note Anonymous Monk How come when I run this script ... it works just fine, but when I try using it in a bigger program it gives me the ":No such file or directory found at lingo4.pl line 508" error? Because [href://http://en.wikipedia.org/wiki/Working_directory|cwd] is cwd and and readdir doesn't return absolute paths If you opendir /a/s/d/f and readdir returns . .. foo.txt, then if you try to open foo.txt, you're trying to open cwd()/foo.txt not /a/s/d/f/foo.txt, so open will fail you should have [id://1012220|used File::Find::Rule] Because your bigger program is unwieldy subroutine declarations are mixed with the main code -- write a single subroutine called Main, and confine the main logic of your program there -- see template at [id://45547] (and see one discussion of that template at [id://805549] your code is 11 times as long as it should be -- you know how to make subroutines, so write subroutines, don't copy/paste the same code (same loops) 11 times You're using short and/or meaningless variable names and putting the meaning in comments -- just use meaningful variable names :) (sub folder) you already know how to use hashes, so don't code long if/else structures to return an integer, use a hash (calling folder) dozens of while loops are not a substitute for a giant if/else structure -- which you wouldn't need if sub folder teturned a string instead of an integer or just have sub folder take care of the printing and while you're at it "folder" is a terrible name for a "sub" -- call it sub processFolder If you have 14 minutes, watch [id://902524|String Calculator TDD Kata done in Perl] , then rewrite your code in a similar fashion <c> my %korpusEng; sitKorpusInHash( \%korpusEng , 'korpusENG.txt' )l ... </c> Another example [id://997733|Out of memory and While replacements with excel XLSX application] / [href://?showspoiler=997792-10;node_id=997792|Re^2: Out of memory and While replacements with excel XLSX application] good luck 1012603 1012603 11