How make difference between 2 files in ABAP

Question

Dear all,
I need some help to make a difference between 2 text files.
I know the function 'SYSTEM' to launch an UNIX command :
  TYPES :
          BEGIN OF ty_delta_data,
            data   TYPE string,
          END OF ty_delta_data.
  DATA :   lt_delta_data    TYPE TABLE OF ty_delta_data.
CONCATENATE 'diff -f'                            "--> command UNIX to have difference between the 2 following files
                           lw_cur_file_data           "--> content path + name file
                           lw_prev_file_data
                          '| grep F5'
         INTO lw_unix_cmd SEPARATED BY space.
  CALL 'SYSTEM' ID 'COMMAND' FIELD lw_unix_cmd
                ID 'TAB'     FIELD lt_delta_data[].
Unfortunately I have a dump :
STRING_BAD_REF
Error analysis
    When accessing a string reference, an invalid value has been detected:
    String reference (hexadecimal): 0038003300310037
    String header Id: 3211319
    String header Id (hexadecimal): 00310037
    Shared objects Id (hexadecimal): "1C0019"
    Shared objects lock flag: 1
    Check value (hexadecimal): 00
    The check value should be hexadecimal "C1".
    However, in this case, it is not.
Have you got an idea about this?
Do you think there is other solution?
Thank you very much in advance.
Best regards,
Robin

Answer 1

Hi Robin,
The error is that strings are not supported by kernel/C/OLE calls. You must use C type.
Anyway, you must not use SAP internal statements (CALL, SYSTEM-CALL, ...). The official API for calling OS commands is SXPG_COMMAND_EXECUTE -> http://help.sap.com/saphelp_nw70/helpdata/en/fa/0971fb543b11d1898e0000e8322d00/frameset.htm
BR
Sandra