Your split doesn't match your data -- the whitespace before the = is optional (zero or more instances) but required after the sign (one or more instances). Change the + to a * and it will probably work better.

You might put a debugging line after the split, just to see what's in $var and $value: print "\$var is ->$var<-\t\$value is ->$value<-\n"; Besides that, I had things backwards in the original version of my code. Try this instead: $value = $env_var{$1} . $value; That way, it won't go in the wrong place. Oops!