How to merge two folders?

There is A folder where the files are stored, it is read various services. On the server there is a new folder B. is it Possible somehow to their virtual smiriti so that the destination folder name has also left A, but when you create new files, they were written to folder B. hence when you request a new file from A, they easily stretched out of B (since by the first condition, the new file should be created there in A).
How is this to implement if possible? What tools to look at?
April 3rd 20 at 18:42
3 answers
April 3rd 20 at 18:44
"ln-s A B" will create A link inside folder B. But will not combine them into one - coleman commented on April 3rd 20 at 18:47
even putilovo to stamp references. - casimir_Adams32 commented on April 3rd 20 at 18:50
April 3rd 20 at 18:46
to merge two directories using the cascade mounting
Googly Unionfs, Aufs, overlayfs kernel.
examples of tyrnete in bulk.
there are differences in the capabilities, functionality, stability...
April 3rd 20 at 18:48
1. a specific task what you pitesa to do
what language is the engine I want to do. may have a solution not using what you suggested for example
it's one of ifka in softinka
so tell me what exactly doing and why

Find more questions by tags LinuxDebian