sh function for finding the first existence of a file in a parent directory. Usage: `lsup [path] file`

lsup.sh

lsup() {
  if [ $# -eq 1 ]; then
    local file=${1} path=$(pwd)
  elif [ $# -eq 2 ]; then
    local file=${2} path=$(realpath -es "${1}")
  else
    echo >&2 "Usage: lsup [path] filename"
    echo >&2 "  At least filename is required"
    return 1
  fi
  [ -z "${SH_DEBUG-}" ] || echo >&2 "Searching for ${file} from ${path}…"
  
  until [ -e "${path}/${file}" ]; do
    [ -z "${SH_DEBUG-}" ] || echo >&2 "Not found in ${path}"
    [ -n "$path" ] || return 1;
    path=${path%/*}
  done
  
  echo "${path}/${file}"
}