setvtrgb --VERSION (return code: 0)
setvtrgb: invalid option -- '-'
setvtrgb from kbd 1.15.5
setvtrgb --help (return code: 0)
setvtrgb: invalid option -- '-'
Usage: setvtrgb vga|FILE|-
If you use the FILE parameter, FILE should be exactly 3 lines of
comma-separated decimal values for RED, GREEN, and BLUE.
To seed a valid FILE:
cat /sys/module/vt/parameters/default_{red,grn,blu} > FILE
and then edit the values in FILE.