http://www.perlmonks.org?node_id=950022


in reply to Parens mess up regex substitute

but I want to know why parens in the variable screwed up one substitute but not the other one

The first argument of the substitution operator is {expected to be|treated as} a regex pattern.

The regex pattern «f(il)e» (line 7) matches the string «file» and captures «il» in $1 or some such variable.

The regex pattern «f\(il\)e» (line 11) matches the string «f(il)e».