allow abbreviations in nfctl CLI

[Kenneth Bingham]

For example, when it's necessary to specify a type of thing to list you could accept a short form of the full, valid type as long as its unambiguous.

$ nfctl list net
# in lieu of
$ nfctl list networks

and

$ nfctl --network "ACME Network" list end
# in lieu of
$ nfctl --network "ACME Network" list endpoint

It may also be possible to support abbreviated, unambiguous sub-commands like

$ nfctl --network "ACME Network" create endpoint

[Russell Allen]

If terminal tab completion is possible, then short versions like end are moot. Simply hit tab to auto complete it. That being said, if the fragment is enough to uniquely identify a term, then that's just as good.

But ... auto-complete doesn't work well for terms with common prefixes like these 3: services, service-policies, and service-edge-router-policies.

For those cases, using the first letter of each word is effective: s, sp, and serp respectively.

[Kenneth Bingham]

@Russell-Allen Yes, argument auto-completion is a feature of nfctl. It may be configured like this:

$ eval "$(register-python-argcomplete nfctl)"
# or
$ source <(register-python-argcomplete nfctl)

Auto-complete works for sub-commands and choices. Example of sub-command is list in nfctl list and choices are like endpoints in nfctl list endpoints.

I see what you mean about choices with that begin with a similar string of characters. I'll give some thought to the possibility of using acronyms. I think I can generate those choices without making things too complex.