What is the usefulness of /dev/null 2>&1 in Cron?

[Shine]

For instance,
if I have a .pl script, or .php script, I could simply execute on my terminal

]# php /path/to/my/script.php

and make the code executed.

So, adding a cron job to run every 5 minutes for this script, can be written like this:

5 * * * * php /path/to/my/script.php

And the question is:
what is the difference between that statement, and, say:

5 * * * * /usr/bin/php /path/to/my/script.php > /dev/null 2>&1

I've searched the web for a detailed explanation but, I cannot find anything.
Would you explain me this please?
Or show me a page with this issue.

Thanks a lot.

[TiTex]

5 * * * * /usr/bin/php /path/to/my/script.php > /dev/null 2>&1

as far as i know this redirects ( > ) any output from script.php to /dev/null ... which is nowhere (like a black hole) , and stderr ( 2 ) is redirected to ( >&1 ) stdout which is already redirected to nowhere , basicly it makes your script run silently and doesn't generate any output or error log/file

i hope i'm not mistaken