how can i check cron tab log

[eluser]Angel Lay[/eluser]
mystructure is
eg : /home/~username/public_html/mysubfolder/mysubfolder2/mycodeigniter/system/application/controllers/controller/method


I tried as below:

Code:

php -q /home/myroot/~username/mysubfolder/cron.php 2>&1 >> /var/log/my_log.log
or
php -q /home/~username/myroot/mysubfolder/cron.php 2>&1 >> /var/log/my_log.log

Code:

php -q /home/~username/myroot/mysubfolder/mysubfolder2/mycodeigniter/system/application/controllers/mycontroller/mymethod 2>&1 >> /var/log/my_log.log

whatever, i haven't got log file and cronjob can't work.