The phrase "a command of a" is not correct and does not convey a clear meaning in written English.
It may be intended to refer to having knowledge or mastery of something, but it lacks context to be usable.
Example: "He has a command of a variety of programming languages."
Alternatives: "a mastery of" or "an understanding of".
Or does it just take a command of a zillion phone numbers?
Supergrass has a command of a variety of pop styles, which it moves between with easy virtuosity.
According to the CECR, "Has a command of a lexical repertoire of 7,675 words and 1,870 phrases" is the requirement for advanced users.
Table 2 Vocabulary descriptors in the CECR Levels of requirements Range & control Basic Has a command of a lexical repertoire of 4,795 words and 700 phrases (including the vocabulary learned at senior secondary education), among which 2,000 words are active vocabulary, which a learner should be able to make skillful use in spoken and written English on the basis of recognition.
Advanced Has a command of a lexical repertoire of 7,675 words and 1,870 phrases (including the vocabulary learned at senior secondary education, vocabulary learned at Basic and Intermediate Requirement levels), among which 2,360 words are active vocabulary (including the vocabulary learned at Basic and Intermediate Requirement levels).
Intermediate Has a command of a lexical repertoire of 6,395 words and 1,200 phrases (including the vocabulary learned at senior secondary education and vocabulary learned at Basic Requirement level), among which 2,200 words are active vocabulary (including the vocabulary learned at Basic Requirement level).
Consequently, during this period of regrouping, on the point of moving a command of an army group, there is always a considerable shortage of men.
There were other examples where a potential recruitment candidate's Klout score was looked at for certain role profiles which demanded a command of an online audience or deep understanding of social networks.
He was phenomenally industrious as a researcher, and had a command of powerful, emotional narrative.
A command of languages and dialects played a large part in her characterizations as well.
Brecht was, first, a superior poet, with a command of many styles and moods.
