Sir Richard C. Jebb, Commentary on Sophocles: Oedipus Tyrannus

[543] οἶσθ᾽ ὡς πόησον; In more than twelve places of the tragic or comic poets we have this or a like form where a person is eagerly bespeaking attention to a command or request. Instead of οἶσθ᾽ ὡς δεῖ σε ποιῆσαι; or οἶσθ᾽ ὥς σε κελεύω ποιῆσαι; the anxious haste of the speaker substitutes an abrupt imperative: οἶσθ᾽ ὡς ποίησον; That the imperative was here felt as equivalent to “you are to do,” appears clearly from the substitutes which sometimes replace it. Thus we find （1） fut. indic.; Eur. Cycl. 131 “οἶσθ᾽ οὖν ὃ δράσεις;” Eur. Med. 600 “οἶσθ᾽ ὡς μετεύξει καὶ σοφωτέρα φανεῖ;” where the conjectures δρᾶσον （Canter） and μέτευξαι （Elmsley） are arbitrary: so with the 1st pers., Eur. IT 759 “ἀλλ᾽ οἶσθ᾽ ὃ δράσω;” （2） a periphrasis: Eur. Supp. 932 “ἀλλ᾽ οἶσθ᾽ ὃ δρᾶν σε βούλομαι τούτων πέρι;” Only a sense that the imperat. had this force could explain the still bolder form of the phrase with 3rd pers.: Eur. IT 1203 “οἶσθά νυν ἅ μοι γενέσθω” = ἃ δεῖ γενέσθαι μοι: Aristoph. Ach. 1064 “οἶσθ᾽ ὡς ποιείτω” = ὡς δεῖ ποιεῖν αὐτήν, where ποιεῖτε is a conjecture. There is no reason, in logic or in grammar, against this “subordinate imperative,” which the flexible Greek idiom allowed. Few would now be satisfied with the old theory that οἶσθ᾽ ὡς ποίησον stood, by transposition, for ποίησον, οἶσθ᾽ ὡς;