shell - BASH: Writing a Script to Recursively Travel a Directory of N Levels

Question

I have the following directory structure for example:

/test_dir/d
/test_dir/d/cron
/test_dir/d/cache
/test_dir/d/...(more sub dirs)
/test_dir/tree
/test_dir/tree/a
/test_dir/tree/a/a1
/test_dir/tree/a/a2
...(and so on for b/ and c/ )

I've written the following bash script that effectively travels to the second level of /test_dir so it will reach /test_dir/d/cron or /test_dir/tree/a but will not go further. I cannot figure out why the recursive script will not travel further can someone please debug the script and point out my error?

here is what I have written:

#!/bin/bash

#script to recursively travel a dir of n levels

function traverse() {   

for file in `ls $1`
do
    #current=${1}{$file}
    if [ ! -d ${1}${file} ] ; then
        echo " ${1}${file} is a file"
    else
        #echo "entering recursion with: ${1}${file}"
            traverse "${1}/${file}"
    fi
done
}

function main() {
    traverse $1
}

main $1

here is the output:

/test_dir/a is a file
/test_dir/b is a file
/test_dir//dcache is a file
/test_dir//dcron is a file
/test_dir//dgames is a file
/test_dir//dlib is a file
/test_dir//dlog is a file
/test_dir//drun is a file
/test_dir//dtmp is a file
/test_dir/movies is a file
/test_dir//treea is a file
/test_dir//treeb is a file
/test_dir//treec is a file
/test_dir//treed is a file

I know there are probably more elegant one line commands to do this. But im trying to do it in this explicit manner. I apologize for the length of this post.

EDIT: using traverse "${1}/${file}"

Answer 1

Several problems with the script. It should be like this:

#!/bin/bash

#script to recursively travel a dir of n levels

function traverse() {
for file in "$1"/*
do
    if [ ! -d "${file}" ] ; then
        echo "${file} is a file"
    else
        echo "entering recursion with: ${file}"
        traverse "${file}"
    fi
done
}

function main() {
    traverse "$1"
}

main "$1"

However, the correct way to recursively traverse a directory is by using the find command:

find . -print0 | while IFS= read -r -d '' file
do 
    echo "$file"
done