The phrase "a great command" is correct and usable in written English.
It can be used to refer to a strong or impressive directive, authority, or skill in a particular area.
Example: "The general issued a great command that inspired his troops to push forward despite the odds."
Alternatives: "an impressive directive" or "a powerful order."
He has a great command of pacing, he's got some good technical things.
"Tremendous insight, a tremendous knowledge of personnel, a great command of the intricacies of the game from a strategic standpoint".
Mr. Obama was powerful, forceful and in control, and had a great command of facts and figures.
She said: "It has been reported that this woman did not have a great command of English or was fully aware of her rights under Irish law.
"At the time it was a campaign, the governor wasn't selecting it, but what I saw in Senator Clinton was an innate ability to move people and a great command over substantive material.
And in industrial applications – building and manufacturing, yes, I can see this would work very well: "Show House Plans" for instance, would be a great command for a building app.
The only thing a playwright should be concerned with winning is a greater command over the truth and his art.
But a transcript would most likely show that Mr. Quinn displayed a greater command and offered more specifics.
I always loved a Sabeth days letter, for then you had a greater command of your time — but hush to all complaints.
On the air, he castigated Emanuel as a practitioner of "the politics of personal destruction," before switching the subject to an area in which he clearly felt a greater command — the still simmering Acorn scandal.
But the movie is smart and tightly drawn; it has a throat-gripping urgency and some serious insights, and Scott has a greater command of space and a more explicit way with violence than most thriller directors — Ferris gets mashed like a Florida orange in a squeezer.
