dir1
    ├── a
    │   ├── b
    │   │   └── file1
    │   └── file2
    ├── c
    │   └── d
    │       ├── e
    │       │   └── file4
    │       └── file3
    └── file5

#!/bin/bash
#desc: get file from directory
#example: sh getfilefromdir.sh A B

INIT_PATH=${1%/}
SAVE_PATH=${2%/}

function checksavepath() {
    if [ -d $SAVE_PATH ]
    then
        rm -rf $SAVE_PATH
    fi

    mkdir ${SAVE_PATH}
    touch $SAVE_PATH".log"
}

function getfilefromdir(){
    for file in ` ls $1`
    do
        if [ -d $1"/"$file ]
        then
            getfilefromdir $1"/"$file
        else
            local path="$1/$file"
            local name=$file
            if [ ! -f $SAVE_PATH"/"$name ]
            then
                echo "cp ${path} to ${SAVE_PATH}/${name}"
                cp ${path} "${SAVE_PATH}/${name}"
            else
                echo "${path} file already exists"
                echo "${path}" >> $SAVE_PATH".log" 2>1
            fi
        fi
    done
}

checksavepath

for sfol in ${INIT_PATH}
do
    getfilefromdir ${sfol}
done

sh getfilefromdir.sh dir1/ dir2

dir2
├── file1
├── file2
├── file3
├── file4
└── file5