please help!!

i want to /htdocs/html/something.php to run every 15 minutes, the command i got was something like:

0, 15, 30, 45 /htdocs/html/something.php

looks right but doesnt work

Thanks,
Eddie

that "command" looks like a crontab entry

the "command" doesnt work tho

read the user contributed notes also

Is it something like this?

crontab - -u username < '30 0 * /htdocs/html/something.php

/htdocs/html/something.php: cannot open ?: no such file

but the file is like
<?

$log = "gsgs";