Grammar JLPT Level N4 - Lesson 27

In Japanese, there are numerous ways to express an order, command, or instruction. The most direct, abrasive, and therefore least used method is called the imperative form, which happens to be one of the basic conjugations of verbs.
Without particles following it, the imperative form is fairly uncommon in daily life, but will often be seen on traffic signs, posters, or banners. In addition, it can be also heard shouted at demonstrations, when cheering at sports events, or in urgent situations, such as an officer yelling at a suspect to stop.
Verbs are conjugated into the imperative form in the following way. For う-Verbs, simply replace the last kana of any verb with the equivalent え sound kana from the same row. For る-Verbs, replace る with either ろ or よ.

• 道路標識(どうろひょうしき)：「止(と)まれ！」
  Road sign: 'Stop!'
• 警察官(けいさつかん)：「手(て)を上(あ)げろ。」
  Policeman: Raise your hands!

The imperative form may sometimes be softened with the particle よ. This is a pattern which is mostly used by men that are familiar with each other, in order to offer advice or encouragement. Women tend to use the more polite て-form of verbs instead.

• 元気(げんき)出(だ)せよ。
  Cheer up!
• 頑張(がんば)れよ。
  Just give it your all!

Any verb except for ある and いる may be conjugated to the imperative form, due to their meanings being based on existence and nothing more.