PHP cURL One Liner？

So im trying to execute a terminal cURL command within a PHP script

The command in question

curl -H "public-api-token: mykeyhere" -X PUT -d "urlToShorten=google.com" https://api.shorte.st/v1/data/url

The response is a JSON and is as follows

 {"status":"ok","shortenedUrl":"http:\/\/sh.st\/XXXX"}

I put it in my PHP script as follows, hoping it would add to a smaller and more effective code footprint

 $cmd='curl -H "public-api-token: mysecretkey" -X PUT -d "urlToShorten=google.com" https://api.shorte.st/v1/data/url';
 exec($cmd,$result);
 print_r($result);

However the returned array is empty

The result is

 Array ( )

exec() returns the last line of output, try using shell_exec().