Bash Shell recursively implements file copy in directory

PrefaceThere is a problem with working today, if you copy the file in directory A to directory B (without the file in directory B), and keep the file structure in directory A. The project focuses on the following: You need to keep the structure of the file in directory A in directory B. Suppose that a directory file A/test/1.txt, transfer to directory B should be b/test/1.txt. You also need to consider whether there is a test directory in directory B, and the multilevel directory should consider recursion. (Fortunately, it's easier to write a recursive traversal of a directory in the Bash shell.)     You need to consider whether the file in a has a file with the same name in B, and if it does, it does not need to be copied. The project requirements sample diagram is as follows:

ImplementProject requirements have, know the design to recursion, the code is very good to write. Here is a demo example for everyone to refer to.

#!/bin/bash

function Recursive_copy_file ()
{
    dirlist=$ (ls $) for
    name in ${dirlist[*]}
        do If [-f $1/$name];
            then # If it is a file and the file does not exist, copy the
            if [!-f $2/$name], then
                CP $1/$name $2/$name
            fi
        elif [-D $1/$name ];
            then # If it is a directory, and the directory does not exist, create a directory
            if [!-D $2/$name]; then
                mkdir-p $2/$name
            fi
            # recursive copy
            Recursive_copy_file $1/$name $2/$name
        fi
    done
}

source_dir= "/tmp/test/system"
dest_dir= "/tmp/test/systemback"

recursive_copy_file $source _dir $dest _dir