DB<22> p $_ = join "," , A..E
A,B,C,D,E
  DB<23> p m/(,.*,)/  # longest possibility from first comma to last comma
,B,C,D,
  DB<24> p m/(,.*?,)/ # shortest possibility from first comma to next comma
,B,
  DB<25> p m/(,.*$)/  # longest possibility from first comma to end of line
,B,C,D,E
  DB<26> p m/(,.*?$)/ # shortest possibility from first comma to end of line
,B,C,D,E
  DB<27>