This tool concatenates all the files in a directory, with a line at the start of each new file giving the name of the file. This is used for testing tools generating multiple output files. It is similar to 'tail -n +1 dir/*'. The main difference is that it assembles files in the same order on all platforms, a characteristic necessary for testing.
Copyright (c) 2020-2021, eBay Inc. Initially written by Jon Degenhardt