Shell Programming and Scripting

sed -e 's/",/"|/g' -e 's/\([0-9]\),/\1|/g' input_file

"nelson,bill","bill","123 Main St","Mpls","MN",55444,8877,william,foo

BEGIN { FS=SUBSEP; OFS="|" }

{
  result = setcsv($0, ",")
  print
}

function setcsv(str, sep, i) {
  gsub(/""/, "\035", str)
  gsub(sep, FS, str)

  while (match(str, /"[^"]*"/)) {
    middle = substr(str, RSTART+1, RLENGTH-2)
    gsub(FS, sep, middle)
    str = sprintf("%.*s%s%s", RSTART-1, str, middle,
      substr(str, RSTART+RLENGTH))
  }

  if (index(str, "\"")) {
    return ((getline) > 0) ? setcsv(str (RT != "" ? RT : RS) $0,
sep) : !setcsv(str "\"", sep)
  } else {
    gsub(/\035/, "\"", str)
    $0 = str

    for (i = 1; i <= NF; i++)
      if (match($i, /^"+$/))
        $i = substr($i, 2)

    $1 = $1 ""
    return 1
  }
}