Here is a shell one-liner that will pull the headers from a web server and display the HTTP/1.1 response status code(s).
cURL + grep
Use the following cURL command and pipe it to grep like so:
Run it from your command line with the appropriate URL. This runs curl in silent mode, follows any redirects, pulls the HTTP headers, and then pipes them to grep. grep will print the HTTP status code to standard output.
HTTP Status Codes
HTTP Status Code Summary (via @stevelosh)
1xx: hold on
2xx: here you go
3xx: go away
4xx: you f$*%ed up
5xx: I f$*%ed up