$ [sudo] pip install mac-opera

$ [sudo] npm i -g mac-opera

$ export OPERA_TIMEOUT=10 # 5 by default

$ opera urls
https://github.com/
https://google.com/
$ opera url
https://github.com/

$ opera open "https://github.com/" "https://google.com/"
$ opera refresh "https://github.com/"

$ opera fullscreen-enter
$ opera fullscreen-detect
1
$ opera fullscreen-exit

$ opera frontmost
0

$ opera pid
42
$ opera isready 5 # timeout 5 seconds
1
$ opera kill