Twitter changed their API, need a bearer token now.

$ curl --request GET --url 'https://api.twitter.com/1.1/users/show.json?screen_name=twitterdev' --header 'authorization: Bearer ' $ curl --request GET --url 'https://api.twitter.com/1.1/users/show.json?screen_name=twitterdev' --header 'authorization: OAuth oauth_consumer_key="consumer-key-for-app", oauth_nonce="generated-nonce", oauth_signature="generated-signature", oauth_signature_method="HMAC-SHA1", oauth_timestamp="generated-timestamp", oauth_version="1.0"' $ twurl /1.1/users/show.json?screen_name=twitterdev

https://developer.twitter.com/en/docs/accounts-and-users/follow-search-get-users/api-reference/get-users-show