Friday television

“Be My Valentine, Charlie Brown”8 p.m. ABC — When Sally sees the box of candy Linus brought for his teacher, she thinks it’s meant for her. “Undercover Boss”8 p.m. CBS — The chief executive officer of Gigi’s Cupcakes struggles with the pressures while under cover. “Hawaii Five-O”9 p.m. CBS — The members of the Five0 investigate a journalist’s past after he is killed. “Shark Tank”9 p.m. ABC — Customized sandals; gold- mining bucket; and sports bra. “Blue Bloods” 10 p.m. CBS — Erin must bring a mob informant back to New York to help with a case after losing her star witness.