coreutils VS tac

An alternative implementation that aims to be compatible with POSIX (not necessarily compatible with GNU coreutils): https://github.com/GrayJack/coreutils

Like https://github.com/GrayJack/coreutils?

cat just regurgitates the contents of the file, but the resulting piped fd is non-seekable. Since almost every command that can operate on a file from stdin can also operate on the file by name/path, at best this is just a needless invocation of a process (i.e. `tv foo.csv` should have been used instead of `cat foo.csv | tv`) - if the app in question can't handle paths, then you can have the shell pipe the file into it instead (e.g. `tv < foo.csv`). At worst, the recipient program would need to buffer the entire contents of the input if it needs to perform non-sequential operations on the source data - this is the case with things like `tac` that need to seek to the end of the input (see https://github.com/neosmart/tac for how `cat foo | tac` requires buffering but both `tac foo` and even `tac < foo` don't).