I could easily be doing something very odd - I only started learning Perl a few days ago. Is grep not a Perl function?
What I am trying to do is to retrieve the line of my file that contains the variable $prop, which is fed in on the command line, and store that entire line in a variable. When I try implementing the code that pelagic sent, I get the entire file output, instead of just the one line I want - odd since the input string is unique.