Thanks, me storing references is very interesting. At first I did not see exectely where your code does difeer to mine in that point, simply because I did not know the perl reference/value syntax. I was expecting a python like approach, but was wrong.

The interesting thing is that my script has \$1 .... which if I understand correctly would be references for python, but actually I user double quotes in th ebash script which requires me to pu \$1 to avoid $1 to be replaced by the shell. This I expect perl to see "$1,$2,$3..." without backslash, eg. value. Am I wrong here ?

The reason I use double quotes is that later thea ctual additional filtering conditions will be injected via shell variable depending on the bash function call arguments.

But I realize that actually my variable name for th earray "$m" was wrong and should be "@m". Cannot try now, but will give it a try tomorrow.