xtrlock(1x) on Linux
The text 765f4b4c7b6b, as Debian 8 (Jessie) shipped it.
Lock X display until password supplied, leaving windows visible
Flags it lists
-
-b
The text 765f4b4c7b6b, as Debian 8 (Jessie) shipped it.
Lock X display until password supplied, leaving windows visible
-b