mkdir /tmp/merkle-tree-test/
cd /tmp/merkle-tree-test/
mkdir -p a/b/ a/c/ d/
echo "one"   > a/b/one.txt
echo "two"   > a/c/two.txt
echo "three" > d/three.txt
merkle-tree . # output is       be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3
merkle-tree . # output still is be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3
echo "four"  > d/four.txt
merkle-tree . # output is now   b5464b958969ed81815641ace96b33f7fd52c20db71a7fccc45a36b3a2ae4d4c
rm d/four.txt
merkle-tree . # output back to  be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3
echo "hidden-five" > a/b/one.txt
merkle-tree . # output changed  471fae0d074947e4955e9ac53e95b56e4bc08d263d89d82003fb58a0ffba66f5