You can easily test a a website availability from the Linux command line and get the status codes from the web-server using commands like TELNET or CURL.
Check a website availability with CURL
Execute the following command to check whether a web site is up, and what status message the web server is showing:
$ curl -Is http://www.shellhacks.com | head -1 HTTP/1.1 200 OK
Status code ‘200 OK’ means that the request has succeeded and a website is reachable.
Here is an another example that shows you how
curl displays different status codes.
$ curl -Is http://shellhacks.com | head -n 1 HTTP/1.1 301 Moved Permanently
You’ll notice that if you visit: http://shellhacks.com you are redirected to http://www.shellhacks.com, because I prefer to have
www in my site’s URL. I do this by implementing a 301 Redirect (Permanently moved) for any visitor who goes to http://shellhacks.com.
You can also check the availability of a particular page on the site:
$ curl -Is http://www.shellhacks.com/en/Bash-Colors | head -n 1 HTTP/1.1 200 OK
Read more: Status Code Definitions
Check a website availability with TELNET
You can also test website availability and get the response code using
$ telnet www.shellhacks.com 80 Trying 18.104.22.168... Connected to www.shellhacks.com. Escape character is '^]'. HEAD / HTTP/1.0 HOST: www.shellhacks.com <PRESS ENTER> <PRESS ENTER>
You will get the output as follows:
HTTP/1.1 200 OK Server: nginx/1.1.10 Date: Sun, 26 May 2013 19:29:46 GMT ***
That also means that the website is OK.