in reply to Insert comma after every character
If the result is to have a comma after each character, save the last one:
$perl -we "($_='FBD') =~ s/(.)(?!$)/$1,/g; print;" ~~Output~~ F,B,D
the assertion of any character with a zero assertion of not at the end of line should do fine.
Good luck. -c
Update: fixed typo...