in reply to Re^2: Use of Uninitialized value in substitution (s///)
in thread Use of Uninitialized value in substitution (s///)

That's not "putting a space after the =", that's breaking the =~ operator by spelling it wrong. Crazy? What's crazy is thinking that putting spaces in the middle of operators should have no effect. Thinking = ~ should work is as crazy as thinking that e q should work, or s ub, or m y.