The bare imperative is blunt to the point of rudeness and mostly appears in signs, sports and fiction. Knowing it matters more for reading than for speaking.
Also known asimperative form命令形meireikeijapanese commands
How the 命令形 is formed
Group I: shift the final う-row kana to the え-row (no る). Group II: replace る with ろ. Group III is irregular. It is blunt — orders, signs, cheering.
Ending
命令形becomes
Example
Group I (う-verbs)
う
え
会う → 会え
つ
て
立つ → 立て
る
れ
割る → 割れ
く
け
書く → 書け
ぐ
げ
泳ぐ → 泳げ
ぬ
ね
死ぬ → 死ね
ぶ
べ
遊ぶ → 遊べ
む
め
休む → 休め
す
せ
探す → 探せ
Group II (る-verbs)
る
ろ
食べる → 食べろ
る
ろ
起きる → 起きろ
る
ろ
閉じる → 閉じろ
Group III (irregular)
来るkoi
来い
来る → 来い
する
しろ
する → しろ
※ くれる (Group II) is an exception: its imperative is くれ, not くれろ. The prohibitive (“don't …”) is the dictionary form + な: 見るな.