使用php ubuntu中的cron作业每2分钟运行一次url不起作用

i want to execute a url for every 2 min in php so i followed the steps

1) crontab -e 
2)select nano editer
3)insert the line

* * * * * /usr/bin/GET http://www.gmail.com/sendMail

After saving the file I got the response

no crontab for root - using an empty one
crontab: installing new crontab

Is there any wrong with the command. Can any one help me out.

you can use curl for hitting URL

follow following steps :

crontab -e

add following line to the file

*/2 * * * * /usr/bin/curl www.google.com

to know more about curl you can do

man curl