On Linux I use the strace command a lot to find out what a kernel calls a binary is executing internally; on Mac OS X this does not exist. In OS X you have, instead, the very powerful, but less easy to use dtrace tool (originally made by Sun for Solaris).
So here is a simple script to get that strace feel under OS X with dtrace:
dtruss -f -t open $@
I put it in /usr/sbin/strace, but anywhere in your path or where it is convenient will do. You need root perms to run it.