vlock man page
vlock — Virtual Console lock program
vlock [ -a,--all ] [ -c,--current ] [ -h,--help ] [ -v,--version ]
vlock is a program to lock one or more sessions on the Linux console. This is especially useful for Linux machines which have multiple users with access to the console. One user may lock his or her session(s) while still allowing other users to use the system on other virtual consoles. If desired, the entire console may be locked and virtual console switching disabled.
By default, only the current VC (virtual console) is locked. With the -a,-all option all VCs are locked. The locked VCs cannot be unlocked without the invoker's password. And, for the paranoid, vlock makes it a trying experience for those attempting to guess the password, so unauthorized access to session(s) is highly unlikely.
Please note that it is entirely possible to completely lock yourself out of the console with the -a,--all option if you cannot remember your password! Unless you are able to kill vlock by logging in remotely via a serial terminal or network, a hard reset is the only method of “unlocking” the display.
vlock works for console sessions primarily. However, there is support for trying to lock non-console sessions as well, but that support has not been well tested.
Lock all console sessions and disable VC switching.
Lock the current session (this is the default).
Print a brief help message.
Print the version number of vlock.
Michael K. Johnson <firstname.lastname@example.org>