[TUHS] Systematic approach to command-line interfaces [ meta issues ]

Larry McVoy lm at mcvoy.com
Sun Aug 1 08:13:17 AEST 2021

On Sat, Jul 31, 2021 at 03:04:48PM -0700, Bakul Shah wrote:
> On Jul 31, 2021, at 12:20 PM, Jon Steinhart <jon at fourwinds.com> wrote:
> > 
> > So I never got getopt().  One of my rules is that I don't use a library
> > in cases where the number of lines of gunk that that it takes to use a
> > library function is >= the number of lines to just write it myself.  Yeah,
> > I know the "but the library has more eyeballs and is debugged" argument
> > but in reality libraries are the source of many bugs.  I've always taken
> > the approach that I would never hire someone who had to use a library to
> > implement a singly-linked list.
> getopt() is perhaps the wrong solution but consider something like MH,
> whose commands all follow a common pattern. Consider:
>   - options (switches) all start with a single '-'
>   - they may be abbreviated to a unique prefix.

That last one is a gotcha waiting to happen:

program --this-is-the-long-option

is the same as 

program --this

but that will break scripts (and fingers) when program gets a new 
option like

program --this-is-the-even-longer-option

We wrote our own getopt() for BitKeeper and it had long and short options
but no gotcha unique prefix.

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