- So long, mom.
- Good-bye, son.

3 seconds sound clip from the All Through the Night (1942) movie soundboard.

You can hear this line at 00:15:08.742 in the Blu-ray version of the movie.

Quote context

[...]

- Aw, now, ma, you can't suspect everybody that comes into the bakery to buy a loaf a bread.

- Yes, but there's something

- What do you want him to do? Spend the rest of his life trying to find out who killed cock Robbin?

- No!

- I know how you feel, but let's be sensible about this. Let the cops handle it.

- You go on home and buy yourself a new hat.

- And here's a couple of hundred bucks for Mrs. Miller. If she needs any more, let me know.

- So long, mom.

- Good-bye, son.

- All right, Barney, drive me home.

- Say, Johnny, did you see a girl come out of here a few minutes ago?

- Excuse me, boss.

- Hey, Saratoga.

- Yes, sir.

- Isn't that my tie you got on?

- Yes, sir.

- And my shirt?

- Yes, sir.

[...]