recursively ls home folder

#!/bin/bash

src=$PWD

listaj() {

        dir=$1
        cd "$dir"

        for file in *
        do
                level=$2
                l=0;
                space=''
                while [ $l -lt $level ]
                do
                        space="${space}\t"
                        l=$(( $l + 1 ))
                done

                echo "${space}${file}" >> $src/tree.txt

                if [ -d "$file" ]
                then
                        listaj "$file" $(( $level + 1 ))
                        cd ..
                fi
        done

}

listaj ~/ 0