TL;DR

Some thoughts about interface consistency.

Most commands in Romeo accept inputs and provide outputs. Most times, inputs come from files, but from time to time they might come directly from the command line.

One such example is the sub-command for validating the Codice Fiscale, an identification code that is used in Italy for several “official” reasons.

I initially designed the interface for the whole set of commands like this:

• output is specified with option -o/--output
• inputs are straight command-line arguments (i.e. those without a switch).

This works fine for most “read many and transform” commands, but it’s sub-optimal for stuff like the Codice Fiscale validation because it’s way easier and intuitive to write this:

romeo cf bcadfe70a01h501j

instead of any of these:

# explicit command-line switch
romeo cf -c bcadfe70a01h501j

# read standard input
echo bcadfe70a01h501j | romeo cf

# shell redirection
romeo cf <( echo bcadfe70a01h501j )

Plus, having a difference in how inputs and outputs are handled always made me uneasy in other scenarios, like ImageMagick or ffmpeg. Should I put -i for inputs or -o for outputs? I always have to look how to do it.

So, I eventually switched to using explicit command-line switches for inputs and outputs, at the expense of providing multiple inputs with multiple occurrences of -i/--input. Which is totally fine, I think.

Cheers and… stay safe!