The list of en- words that can be pronounced /an/ rather than /ɪn/ or /ɛn/ is pretty short. From a quick search of the Carnegie-Mellon Pronouncing Dictionary, these words start with en- and can be pronounced /an/ (some have alternate pronunciations with /ɛn/):

ENCLAVE
ENCLAVES
ENCORE
ENCORES
ENFANT
ENSEMBLE
ENSEMBLES
ENTENDRE
ENTOURAGE
ENTOURAGES
ENTRE
ENTREE
ENTREES
ENTREPRENEUR
ENTREPRENEUR'S
ENTREPRENEURIAL
ENTREPRENEURS
ENTREPRENEURSHIP
ENVOY
ENVOYS

I will note also that Merriam-Webster does also countenance /an/ for envelope. However, few if any other en- words can be pronounced /an/.

Great question!

(A coincidence of https://english.stackexchange.com/a/190692/8286 )

Just FWIW, I say "minus" like you ("l s minus a l") or often just don't say the minus. So, in the example I'd read "n c l p 1234"

IMO very few people say hyphen. I'd say "dash" is common, but I'd say "minus" is more common than "dash".

Purely in my opinion: what she is saying (a) sounds silly and (b) I've never heard it before.

(Indeed, since 'tac' is a common command, it's doubly silly - but that's just me.)

Maybe someone here has heard it before?

Explained! - Military usage

Ahh! A user below has explained that "tac" is in fact military talk for the minus sign or hyphen.

All explained!

Again FYI I have never, ever, ever hear this in a computing / shell context.