Check if a website at URL is up in bash using curl.

urlPing.sh

#!/bin/bash
# FUNCTION 
isSiteUp () { check=`curl -Is $1 | head -1 | awk '{print $2}'`;if [ "$check" = "200" ]; then return 1; else return 0; fi; }

# EXAMPLE USAGE
siteToCheck="https://qrng.anu.edu.au/API/jsonI.php?" #This is a quantum random number api but any url should work.
test=`isSiteUp $siteToCheck`
if [ "$?" = "1" ];then
        echo "The website at: [$siteToCheck] is [ONLINE]"
else
        echo "The website at: [$siteToCheck] is [OFFLINE]"
fi


# Explanation:
#   The isSiteUp function takes a url as arg 1 and returns 1 if the url returned a 200 status code.
#   We use curl to achive this. We tell curl to only fetch the headers (-I) in silent mode (-s). (because a loading bar is annoying)
#   Then we pipe the first header (something like "HTTP/2 200" or "HTTP/1.1 200 OK") into awk to get the status code "200".
#   If it is 200 then return 1 for success, else return 0 for failure.

Please don't crucify me for my shitty bash conventions and syntax. Also this only handles status codes of "200" so if the status is literally anything else when it curl's it then it will say the site is offline. (More info on HTTP status codes)