rm -rf /tmp/mt /tmp/base
mkdir /tmp/mt
svnadmin create /tmp/mt/base
cd /tmp
svn co file:///tmp/mt/base 
cd base
mkdir dir1
svn add dir1
svn -m "test" commit
echo "line1" >>dir1/file1
svn add dir1/file1
svn -m "test" commit
echo "line2" >>dir1/file1
svn -m "test" commit
svn -m"test" cp dir1 dir2
svn -m "test" commit
cd dir2
svn diff -r 2