s /\\([^\\tnrfbae])|\\\\([tnrfbae])
    /(my$x=defined($1)?$1:$2)=~y#tnrfbae#\t\n\r\f\b\a\e#;$x;
    /gex;

##</code><code>##

  s /\\([^\\tnrfbae])|\\\\([tnrfbae])|\\([tnrfbae])
    /(my$x=defined($1)?$1:$2?$2:'')=~y#tnrfbae#\t\n\r\f\b\a\e#;$x?$x:$3;
    /gex;