#!/bin/sh

showusage()
{
  echo "Usage: $0 dir"
  exit 1
}
if [ $# -ne 1 ]; then  showusage;  fi 
if [ ! -d $1 ];  then  showusage;  fi

find $1 -print | awk '
{
  split($0, f, "/")
  l = length(f)
  if( l == 1 )
    line = $0
  else {
    line = ""
    for(i=1; i<l-1; i++)
      line = line  "|   "
    line = line "|--- "  f[l]
  }
  print line
}'