Hi,

You said:

"Problem is I don't really can use any additional modules - only the standard ones (meaning I can't install any additional modules)."

That is almost certainly not true. Why do you think so? What research have you done to find out about it? Would you try a construction project without first visiting the tool store?

• Yes, even you can use CPAN
• local::lib
• https://perlbrew.pl

Then you said:

"there is probably a good module that can do it"

Did you learn Hash::Merge as you were already advised when you asked about this before?

We can't help you if you won't help yourself. Generally, the first step in that process is to let go of your preconceived ideas, which facilitates the second step, i.e. to listen to the advice you get from those who know. If you had spent the 24 hours since your first post on this topic learning to how to install the recommended modules on your system and how to use them, instead of continuing down the path on which you had already become stuck, you could have solved your problem by now and be ready to tackle the next one with new skills.