— Command: autodetach state

(none)
Sets whether screen will automatically detach upon hangup, which saves all your running programs until they are resumed with a screen -r command. When turned off, a hangup signal will terminate screen and all the processes it contains. Autodetach is on by default.

— Command: detach

(C-a d, C-a C-d)
Detach the screen session (disconnect it from the terminal and put it into the background). A detached screen can be resumed by invoking screen with the -r option (see Invoking Screen). The -h option tells screen to immediately close the connection to the terminal (‘hangup’).

— Command: password [crypted_pw]

(none)
Present a crypted password in your .screenrc file and screen will ask for it, whenever someone attempts to resume a detached session. This is useful, if you have privileged programs running under screen and you want to protect your session from reattach attempts by users that managed to assume your uid. (I.e. any superuser.) If no crypted password is specified, screen prompts twice a password and places its encryption in the paste buffer. Default is `none', which disables password checking.