Or for any scripting language, use you can use strace.<p>e.g. to find CGI.pm in perl:<p>$ strace -e open perl -MCGI -e exit 2>&1 > /dev/null | grep CGI.pm | sed -e 's/",.<i>$//' -e 's/^.</i>"//'<p>/usr/share/perl/5.10/CGI.pm<p>Linux specific (use 'truss' on Solaris). I don't think OSX had strace like this last time I looked, but I assume dtrace could do a similar job if there isn't a more specific tool?<p>[Edit - there are literal asterisk chars in the above after the '.' chars in the regex, but I can't see a way to include them in a HN post (backslash escaping or HTML entities don't work)?]