Usage and meaning : 寝ろ vs 寝てろ?


[![enter image description
here](https://i.stack.imgur.com/0qirk.jpg)](https://i.stack.imgur.com/0qirk.jpg)
Source: [page 32, Ch.82 of よつばと！](http://raw.senmanga.com/Yotsubato!/82/32)

My translation of the highlighted text bubble is,

> Now, sleep quietly okay.

But I am confused as to why 寝てろ is used here as opposed to 寝ろ? Is it because
sleep is a resultant state (something like 知っています or けっこんしています)?

After some probing I came across
[this](https://japanese.stackexchange.com/questions/14804/how-to-
translate-%e3%81%a6-form-%e3%82%8d) but it doesn't answer the difference
between usage of 〜てろ and 〜ろ form.

What I did come to know is, 寝てろ is a compact form of 寝ていろ which is
imperative/command form of 寝ている. All in all, 寝ていろ is something like a command
to sleep (or be in state of sleep or keep sleeping?) Why is the progressive
form used here? What kind of subtlety does it add?




This type of いる is called [a subsidiary
verb](https://japanese.stackexchange.com/q/18952/5010), and what it means
roughly depends on the context and the verb type. For details, see: [When is
Vている the continuation of action and when is it the continuation of
state?](https://japanese.stackexchange.com/q/3122/5010)

寝る is an ordinary action verb like 食べる, 走る or 勉強する. It's not an "instant
state-change (aka punctual)" verb like 知る, 結婚する or 倒れる. This means when 寝て
(the te-form of 寝る) is followed by いろ (the imperative form of いる), it usually
means the **continuation** of the action (i.e., "be ～ing"). So 寝ていろ means "Be
sleeping" or "Keep sleeping", while 寝ろ just means "Sleep." or "Go to bed."




This type of いる is called [a subsidiary
verb](https://japanese.stackexchange.com/q/18952/5010), and what it means
roughly depends on the context and the verb type. For details, see: [When is
Vている the continuation of action and when is it the continuation of
state?](https://japanese.stackexchange.com/q/3122/5010)

寝る is an ordinary action verb like 食べる, 走る or 勉強する. It's not an "instant
state-change (aka punctual)" verb like 知る, 結婚する or 倒れる. This means when 寝て
(the te-form of 寝る) is followed by いろ (the imperative form of いる), it usually
means the **continuation** of the action (i.e., "be ～ing"). So 寝ていろ means "Be
sleeping" or "Keep sleeping", while 寝ろ just means "Sleep." or "Go to bed."

