Understanding RGB representations
The most common implementation is RGB24 (24-bit RGB), which is also what I'm going to talk about in this article.
It's 24-bit cause it's 3 bytes, one for each of the colors, Red, Green, and Blue.
these are all the same, just different numerical systems of representation, and you can easily convert these values using the shell.
hex to decimal
$ printf 'rgb(%d, %d, %d)\n' 0xff 0xff 0xff
decimal to hex
$ printf '#%02x%02x%02x\n' 255 255 255
sometimes you end up using floating values like
rgb(0.43, 0.64, 0.31), in which case; you multiply by 255.
But to the main point of this article; stop saying stuff like "rgb or hex?"