Вытряхни песок из ботинок перед входом в дом.

Вытряхни is the informal singular imperative of the perfective verb вытряхнуть. It gives a command to do the action once and completely.

So here it means something like:

• Shake the sand out
• Get the sand out with a shake

If you used вытряхивай, that would be the imperfective imperative. It would sound more like:

• keep shaking it out
• shake it out as a repeated/habitual action
• be in the process of shaking it out

For a simple one-time instruction, вытряхни is the natural choice.

The prefix вы- often adds the idea of out.

• тряхнуть = to give a shake
• вытряхнуть = to shake out

So вытряхни песок из ботинок is literally something like shake the sand out of the boots.

That prefix matches the idea of removing something from inside something else.

Russian usually leaves out subject pronouns when they are already clear from the verb form.

Here вытряхни already tells you that the speaker is talking to one person informally — basically you singular.

So:

• Вытряхни песок... = Shake out the sand...
• Ты вытряхни песок... is possible, but it adds emphasis and is not the neutral form

In commands, leaving out ты is completely normal.

Russian often omits possessive words like my, your, his, etc. when ownership is obvious from context.

In this sentence, if someone is being told to shake sand out of boots, it is naturally understood to mean their own boots.

So Russian says:

• из ботинок = out of the boots

But in natural English, we often need:

• out of your boots

If you really wanted to emphasize your own, Russian could use своих:

• из своих ботинок

But in the original sentence, that would be unnecessary.

Russian has no articles, so there is no direct equivalent of the or a/an.

That means nouns like песок, ботинок, and дом appear without articles, and the listener understands from context whether the meaning is definite or indefinite.

So:

• песок could mean sand or the sand
• дом could mean a house, the house, or home/house depending on context

English has to choose an article, but Russian does not.

Песок is the direct object of вытряхни, so it is in the accusative case.

However, песок is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular looks exactly like the nominative singular.

So:

• nominative: песок
• accusative: песок

That is why the form does not visibly change here.

The preposition из means out of / from inside, and it requires the genitive case.

The dictionary form is:

• ботинки = boots

After из, it becomes:

• из ботинок = out of the boots

So ботинок here is genitive plural.

This fits the meaning perfectly, because the sand is being shaken out of the boots.

It only looks singular if you are expecting a regular ending.

In fact, ботинок here is genitive plural of ботинки.

Russian genitive plural forms are often less predictable, and many nouns have a zero ending in that form.

Compare:

• nominative singular: ботинок = boot
• nominative plural: ботинки = boots
• genitive plural: ботинок = of the boots / out of the boots

So in this sentence, ботинок is definitely plural, even though it looks like the singular dictionary form.

The preposition перед normally takes the instrumental case, and that is why вход becomes входом.

So:

• вход = entrance / entering
• перед входом = before the entrance / before entering

In this sentence, the phrase can be understood as something like:

• before going into the house
• at the entrance to the house, before entering

The important grammar point is that перед requires instrumental here.

Russian uses:

• в + accusative for movement into a place
• в + prepositional for being in a place

So:

• в дом = into the house
• в доме = in the house

In перед входом в дом, the idea is entry or movement into the house, so в дом is correct.

Usually no, not in this phrase.

Домой means home in the sense of to home / homeward, not literally into the house as a physical structure.

So:

• идти домой = to go home
• войти в дом = to enter the house

Here the sentence refers to entering a specific building, so в дом is the right choice.

Not if you want the same meaning.

There is an important difference:

• из ботинок = out of the boots, from the inside
• с ботинок = off the boots, from the outside surface

So if the sand is inside the boots, из ботинок is correct.

If you meant sand stuck to the outside, you would more naturally say something like:

• стряхни песок с ботинок

So the choice of preposition changes the image quite a bit.

Yes. Russian word order is fairly flexible, and changing it usually changes emphasis, not the core meaning.

The original sentence is perfectly natural:

• Вытряхни песок из ботинок перед входом в дом.

But you could also say:

• Перед входом в дом вытряхни песок из ботинок.

This version puts more emphasis on when to do it.

So the meaning stays basically the same, but the most important information can be moved forward for focus.