Suck a file/dirtree into a given folder
You have a dirtree with multiple levels:

    > folder_1
        +---- folder_1_1
                +---- file_1
                +---- file_2
        +---- folder_1_2
                +---- file_3
    ... so on

Now I want it to look like this

    > tgt_folder
        +---- folder_1_folder_1_1_file_1
        +---- folder_1_folder_1_1_file_2
        +---- folder_1_folder_1_2_file_3
    ... so on

Basically it's just a matter of changing path separators from `/` to `_` but for some reason my brain simply can't handle recursions. Please help me not to lose my job. Thank you.
Suck a file/dirtree into a given folder
===

You have a dirtree with multiple levels:

    > folder_1
        +---- folder_1_1
                +---- file_1
                +---- file_2
        +---- folder_1_2
                +---- file_3
    ... so on

Now I want it to look like this

    > tgt_folder
        +---- folder_1_folder_1_1_file_1
        +---- folder_1_folder_1_1_file_2
        +---- folder_1_folder_1_2_file_3
    ... so on

Basically it's just a matter of changing path separators from `/` to `_` but for some reason my brain simply can't handle recursions. Please help me not to lose my job. Thank you.