Let us say we have a collection of ebooks or papers/articles sorted in various folders and we want to create a database (or spreadsheet) of those papers or books so that we can add comments or notes next to them. For example, let us say we have a file structure like ( find . type f ) ./entanglement-entropy-holography/1006.1263.pdf ./entanglement-entropy-holography/0912.1877.pdf ./entanglement-entropy-holography/0911.3160v2.pdf ./entanglement-entropy-holography/0912.1877v2.pdf ./entanglement-entropy-holography/1010.1682.pdf ./graviton-propagator/zee-1979-PhysRevLett.42.417.pdf ./graviton-propagator/dewitt-3-PhysRev.162.1239.pdf ./graviton-propagator/dewitt-2-PhysRev.162.1195.pdf ./graviton-propagator/dewitt-1-PhysRev.160.1113.pdf ./SUSY/Piguet-9710095v1.pdf ./SUSY/Olive_susy_9911307v1.pdf ./SUSY/sohnius-introducing-susy-1985.pdf ./SUSY/khare-cooper-susy-qm-phys.rept-1995.pdf ./SUSY/Instantons Versus Supersymmetry9902018v2.pdf and we want this ...