What will happen if establish what is already installed?

Good day!
VPS Ubuntu.
Yesterday I had a hot day, I inexperience dropped your site several times, several times I wanted to reinstall the system from scratch, but still coped with all the problems without reinstallation, it works! But at a time when lying is the website, I rush to find the exit I tried to install what is already installed. For example, several times used the command:
apt-get install php7.2
apt install php7.2-mysql

Tell me, what is the consequence of the installation installed things?
Thank you!
June 5th 19 at 21:20
2 answers
June 5th 19 at 21:22
Solution
Established things are usually not re-established. But if the installation is not validated (or ignored), it all depends on the installer script.
Installer:
(if not disabled) checks the dependencies and ostanavlivaet what no
(always) lays out the package files to the places where they were assigned to lie
(if provided) backup old configs
(if provided) sets a new config, the old can wipe
(always) updates the information in the database with data about the installed programs
The installation process itself took place in the same way as the first time, there is the interest of abigale and different lines have appeared...

CityCat4, thank You, my good man! - Alfonzo_Hau commented on June 5th 19 at 21:25
June 5th 19 at 21:24
what are the consequences of setting things installed?

A decrease in resource storage. Much less wiping out the configs.
This means that I have now works several php7.2 and php7.2-mysql or just one? Ustanovleny package does not replace the files already installed, and creates another copy?
A decrease in resource storage.

At the time of installation or on constantly? - Alfonzo_Hau commented on June 5th 19 at 21:27
, Install service pack replaces files already installed. This is true for Ubuntu, but not in General for Linux. - Alfonzo_Hau commented on June 5th 19 at 21:30
thanks for the answers! So there may be extra files?
I noticed a jump in CPU load, just at the time that I had to re-install, then load back, then re-install will not affect the reduction of resource storage in the future?

PS. With this recaptcha full Well.. until ponazhimat all the squares, two minutes pass...
Why is she here, because I am already registered.... - chaz commented on June 5th 19 at 21:33

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