RosettaCodeData/Task/URL-encoding/UNIX-Shell/url-encoding.sh

function urlencode
{
  typeset decoded=$1 encoded= rest= c=
  typeset rest2= bug='rest2=${rest}'

  if [[ -z ${BASH_VERSION} ]]; then
    # bug /usr/bin/sh HP-UX 11.00
    typeset _decoded='xyz%26xyz'
    rest="${_decoded#?}"
    c="${_decoded%%${rest}}"
    if (( ${#c} != 1 )); then
      typeset qm='????????????????????????????????????????????????????????????????????????'
      typeset bug='(( ${#rest} > 0 )) && typeset -L${#rest} rest2="${qm}" || rest2=${rest}'
    fi
  fi

  rest="${decoded#?}"
  eval ${bug}
  c="${decoded%%${rest2}}"
  decoded="${rest}"

  while [[ -n ${c} ]]; do
    case ${c} in
    [-a-zA-z0-9.])
      ;;
    ' ')
      c='+'
      ;;
    *)
      c=$(printf "%%%02X" "'$c")
      ;;
    esac

    encoded="${encoded}${c}"

    rest="${decoded#?}"
    eval ${bug}
    c="${decoded%%${rest2}}"
    decoded="${rest}"
  done

  if [[ -n ${BASH_VERSION:-} ]]; then
    \echo -E "${encoded}"
  else
    print -r -- "${encoded}"
  fi
}