Guix

fbcat saves the contents of the Linux framebuffer (/dev/fb*), or a dump therof. It supports a wide range of drivers and pixel formats. fbcat can take screenshots of virtually any application that can be made to write its output to the framebuffer, including (but not limited to) text-mode or graphical applications that don't use a display server.

Also included is fbgrab, a wrapper around fbcat that emulates the behaviour of Gunnar Monell's older fbgrab utility.