In Command-Line Applications, we looked at a Python main-import switch which boiled down to this.

for file in args.file:
    with open( file, "r" ) as source:
        process_file( source, args )

The point was that each distinct file on the command-line was processed in a more-or-less uniform way by a single function …

I'm old -- I admit it -- and I feel that command-line applications are still very, very important. Linux, for example, is packed full of almost innumerable command-line applications. In some cases, the Linux GUI tools are specifically just wrappers around the underlying command-line applications.

For many types of high-volume data processing …