[HaBo]

tr -dc 0-9 < /dev/urandom

REPORT  zrandom_numbers.

DATA: number(4) TYPE n,
      tab_numb  LIKE TABLE OF number,
      seed      TYPE i,
      v_random  TYPE REF TO cl_abap_random_int,
      next_int  TYPE i.

PARAMETERS: p_file TYPE string.

* Random - Generator anschmeißen:
seed = cl_abap_random=>seed( ).
v_random = cl_abap_random_int=>create( seed = seed min = 0000 max = 9999 ).

* Zufallszahlen rein
DO 9999 TIMES.
  next_int = v_random->get_next( ).
  number = next_int.
  READ TABLE tab_numb WITH KEY table_line = number TRANSPORTING NO FIELDS.
  IF sy-subrc IS NOT INITIAL.
    APPEND number TO tab_numb.
  ENDIF.
ENDDO.

* Ausgabe auf Bildschirm (und in Datei)
LOOP AT tab_numb into number.
  WRITE: / Number.
ENDLOOP.

cl_gui_frontend_services=>gui_download(
  EXPORTING
    filename                  = p_file
  CHANGING
    data_tab                  = tab_numb ).

using System;
using System.Linq;
using System.IO;

namespace HaBo
{
  class RandomNumbers
  {
    public static void Main(string[] args)
    {
       File.WriteAllText("random.txt", 
          String.Join(Environment.NewLine, 
             Enumerable.Range(0, 10000)
             .OrderBy(x => Guid.NewGuid())
             .Select(s => s.ToString("D4"))));
    }
  }
}