The imperative form of a verb is used for giving commands. It is made up of three parts:
1. The prefix “بـِ” (pronounced like “be” in “bed”)
2. The present stem of the verb
3. The imperative suffix (plural only)
Here is an example for the verb “to sit”:
If the first vowel of the present stem of the verb has an “o” sound, the prefix changes into “بُـ” (pronounced like “bo” in “bold”).
Kill them! (plural)
The negative imperative structure is exactly like the normal imperative, except that the suffix preceding the verb is “نـَ” (pronounced like “na” in “narrow”).
Don't sit! (singular)
Don't sit! (plural)
The imperative form of the two verbs “بودن” (“to be”) and “داشتن”(“to have”) is not made using the general rule.
As you see, the only difference was that the prefix was omitted. The difference is more dramatic for the verb “داشتن” (“to have”):
Another group of exceptions is the class of combined verbs that their verb part is from the infinitive “کردن” (“to do”) or “شدن” (“to become”). (Actually, there are other verbs that go in this group as well, but there is no rule to distinguish them. They must be learned by experience.) For these verbs, like the verb “to be”, the prefix “بـِ” is omitted. Here are some examples:
به پدرت کمک کن!
کار کنید، تنبلها!
اول مطمئن شو که منم بعد در را باز کن.
Help your father.
Work! You lazy people!
First make sure (lit. become sure) that it’s me (lit. I am me) then open the door.
For all these exceptional verbs, the negative imperative is obtained by simply adding the “نـَ” prefix before them and omitting nothing.
Here is a set of examples containing instances of some different cases.
دشمنانت را بشناس!
عکسِ من را بکِش.
اسمت را بگو.
به این تابلو دست نزن!
لطفاً در اینجا پارک نکنید.
دستت را بده به من.
اینقدر بدجنس نباش.
هیچکس را دوست نداشتهباش.
به گذشته فکر نکن.
اگر خوب کار نکرد اخراجش کن.
این را خوب یاد بگیر.
Know your enemies!
Draw my picture.
Say your name.
Don’t touch this painting!
Please don’t park here.
Give me your hand.
Don’t be so mean.
Don’t love anyone.
Don’t think about the past.
If he\she didn’t work well, fire him/her.
Learn this well.
About the last group of exceptions, it should be added that the verbs “کردن” and “شدن” must always be considered as part of a combined verb:
کمی لاغر شو!
من را رئیس جمهور کنید!
lit. become slim a bit!
Make me president!
They are only considered separate simple verbs when there is no noun in the sentence that could possibly be part of a combined verb. This is the only way they can come with the “بـ” suffix.
همین کار را بکن.
گفتی عصبانی نمیشوم، اما بشو!
Do this (and exactly this) job.
You said I won't get angry, but do [get angry]!
It is important to learn the imperative correctly since its structure is also used in conjugating verbs of the present subjunctive tense. The following table might be helpful for knowing where to use the “بـ” suffix in imperatives.