How to investigate fragmentation of one file? I'd like to see if one of my file is "all over the place", ie fragmented in little pieces at different locations on my hard drive.

I'm not looking for a software like iDefrag but rather a command line utility. I know nothing of file systems, nodes, etc. Does such a CL tool exist? More generally, how do you know where files physically are?

The file I want to investigate is ~/Library/Application Support/Google/Chrome/Default/History indexes, but that's more of a general question.
HFSDebug was a decent tool on older version of OSX, however I do not beleive it is Lion compliant.

http://www.osxbook.com/software/hfsdebug/

The original maker of HFSDebug recommends File Xray, a commercial program to do the same tasks and more - check it out here

http://filexray.com/