opening directory without know its name : Linux shell : Im writting a script in which user inputs the directory in which he wants to find a specific string inside .txt files, but I dont know how to open every directorys inside the given directory withot knowing their names.

For example this is a directory which user specifies:

    Project/
       AX/include/
                 ax.txt
                 bx.txt
       AX/src/
             ax.txt
             bx.txt
       BY/include/
                 ay.txt
                 by.txt
       BY/src/
             ay.txt
             by.txt
