in reply to Re: substituting 1 escaped character for another
in thread substituting 1 escaped character for another

Also note that the backslash in the replacement part is useless and could be even misleading as someone might think that \< has a special meaning.
s/\(/</

If there are more parentheses to replace, use the /g modifier:

s/\(/</g

Also, in case of single character replacements, you can use transliteration:

tr/(/</

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord }map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,