script or tool to walk back thru 1 file's history diffing..

Would like to write a script to follow the history of a single
file, backwards, diffing the file w/it's prior version all the way
back to the 1st version.

By using 'svn info' to get the last chgd rev, and running 'svn
diff -c $lastchgd_rev ...', this seems simple enough if the URL to
the file does not change; but if the pathname in svn to the file
is renamed there is no choice but to look at 'svn log', right?

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thanks/regards,
Tom
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Does such a command line tool already exist?