I use this command to display the history of commits.
svnlook history -r 2 mypath
and I get this:
svnlook: Can't open file 'mypath/format': No such file or directory
I'm sure that "mypath" is correct. I also tried going into deeper directories. I tried with absolute and relative paths, I tried with the -r option and without but I always get the same result.
The svnlook command is used on the server that is hosting the repository (i.e., it's not what you need).
You can use svn to query the working copy for what data you're looking for. Refer to http://svnbook.red-bean.com/en/1.5/svn.tour.history.html and check out svn log or svn diff to get a history of the changes.