I updated the script - now it checks if the CoinGecko API is available, before doing anything else; if not, there is a message and the script terminates (no ugly parse error message anymore).
I figured out that with the "xmessage"-function the prices could be displayed in a pop-up-window; but all the colours would be gone, and the idea behind the script is that the desired information is accessible from and displaying to the command line interface .