I think most gnu utils are written so that they treat input files as a stream of data so you can also use pipes instead of regular files. This also means they c

I think most gnu utils are written so that they treat input files as a stream of data so you can also use pipes instead of regular files. This also means they can somewhat handle size changes since they will keep reading until they encounter an EOF without relying on an earlier snapshot of the file size or sparse chunks. Whether the results are useful depends on the file format, if it's just temporary padding as in this case it works.