How to run cron job every 2 hours?
Solution 1:
Just do:
0 */2 * * * /home/username/test.sh
The 0 at the beginning means to run at the 0th minute. (If it were an *, the script would run every minute during every second hour.)
Don't forget, you can check syslog to see if it ever actually ran!
Solution 2:
The line should read either:
0 0-23/2 * * * /home/username/test.sh
or
0 0,2,4,6,8,10,12,14,16,18,20,22 * * * /home/username/test.sh