source: vendor/bash/3.1-p17/examples/scripts/vtree2

#!/bin/bash
#
# vtree - make a tree printout of the specified directory, with disk usage
#         in 1k blocks
#
# usage: vtree [-a] [dir]
#
# Original posted to Usenet sometime in February, 1996
# I believe that the original author is Brian S. Hiles <bsh29256@atc.fhda.edu>
#
usage()
{
        echo "vtree: usage: vtree [-a] [dir]" >&2
}

while getopts a opt
do
        case "$opt" in
        a)      andfiles=-a ;;
        *)      usage ; exit 2 ;;
        esac
done

shift $((OPTIND - 1))

export BLOCKSIZE=1k     # 4.4 BSD systems need this

[ $# -eq 0 ] && set .

while [ $# -gt 0 ]
do
        cd "$1" || { shift; [ $# -ge 1 ] && echo >&2; continue; }
        echo -n "$PWD"

        du $andfiles | sort -k 2f | sed \
                -e 's/\([^      ]*\)    \(.*\)/\2  (\1)/' \
                -e "s#^$1##" \
                -e 's#[^/]*/\([^/]*\)$#|____\1#' \
                -e 's#[^/]*/#|    #g'
        
        [ $# -gt 1 ] && echo 
        shift
done