To go home. In *nix shells (some of them anyway) the tilde "~" means the home directory (like /usr/home/<your username>/). The cd command means "change directory".
Brave knight: Can I please cross this enchanted bridge?
Troll: NFWC, cunt.
Brave knight: Ah, you used the 'C' and "cunt": how redundant.
Troll: Fuck off, cunt.