Who played Fred Sanford in 'Sanford and Son'?

In which TV series is Hawkeye Pierce a main character? Who played Radar O'Reilly in 'M*A*S*H'? Who played Klinger in 'M*A*S*H'? In which TV series is Klinger a main character? Who played Arthur "Fonzie" Fonzarelli in 'Happy Days'? In which TV series is Arthur "Fonzie" Fonzarelli a main character? Who played Richie Cunningham in 'Happy Days'? In which TV series is Richie Cunningham a main character?