I peruse a fair amount of dotfile repos, and keep seeing people use short flags inside aliases and little command line tools.
Short flags are a command line shortcut, and they do belong there, but if you’re not writing the command in a prompt, do yourself (and anyone else that may someday be reading your code) a favor and be more verbose.
curl --silent checkip.dyndns.org \ | grep --extended-regexp --only-matching '[0-9\.]+'
…is a lot easier for a human to understand than this…
curl -s checkip.dyndns.org | grep -Eo '[0-9\.]+'
Don’t you think?