Traversing directory using depth first search

#!/bin/bash
# Traverse a directory using depth first traversal technique
# Usage $0 directorypath
# otherwise it takes current working directory as directory path

depth()
{
#Do a small depth checking how deep into the tree we are
k=0
while [ $k -lt $1 ]
do
echo -n " "
let k++
#or use k=`expr $k + 1`
done
}

traverse()
{
# Traverse a directory

ls "$1"while read i
do
depth $2
if [ -d "$1/$i" ]
then
echo Directory: $1/$i

traverse "$1/$i" `expr $2 + 1`
# Calling this as a subshell means that when the called
# function changes directory, it will not affect our
# current working directory
# If you call this in current shell it gives the error
# bash: traverse: No such file or directory after changing
# the current directory
else

echo File: $1/$i
fi
done
}

# $1 is directory path

if [ -z "$1" ]
then
# Here we are giving '0' is the current depth of direcory
traverse . 0
else
traverse $1 0
fi