grammar - How do I determine the indirect object of a command?

I'm working my way through the core 2000, and came across this:

[明日]{あす}、6[時]{じ}に[起]{お}こしてください。

I immediately thought, "Please wake up at 6am tomorrow." But the translation in the deck instead says, "Please wake me up tomorrow at six o'clock."

How would I know who the indirect object (the person being woken up) is? Shouldn't "wake me up" be preceded by [私]{わたし}に or similar?

Answer

For one, you are confusing transitive (起こす) and intransitive (起きる) verbs. Your "immediate thought" would be

Please wake up at 6am tomorrow.
明日、6時に 起きて ください。

Secondly, you should keep in mind that the direct object (here, of the transitive verb 起こす) may be omitted, whence

明日、6時に起こしてください。
Please wake [someone] up at 6am tomorrow.

where [someone] = me is implied.