[CentOS] sorting a file

Fri Apr 3 11:03:15 UTC 2009
John Doe <jdmls at yahoo.com>

From: Tom Brown <tom at ng23.net>
> I need to find out how many times an IP address appears in a file - the 
> IP is the first field in the access log string so what would be the best 
> way to sort this file and count how many times each IP address appears ?

grep "^IP " | wc -l

JD