The following code shows the syntax of the FM 'SXPG_COMMAND_EXECUTE'. You pass it the external command created within transaction SM69 and it will execute it.
DATA: ld_comline LIKE sxpgcolist-name, ld_param LIKE sxpgcolist-parameters, ld_status LIKE extcmdexex-status, ld_output LIKE btcxpm OCCURS 0 WITH HEADER LINE, ld_subrc LIKE sy-subrc. REFRESH ld_output. MOVE 'FTP_DATA_IN' to ld_comline. "Maintained using trans SM69 * Execute external command, contained in 'ld_comline' CALL FUNCTION 'SXPG_COMMAND_EXECUTE' EXPORTING commandname = ld_comline * additional_parameters = ld_param "Params passed to script * operatingsystem = 'UNIX' IMPORTING status = ld_status TABLES exec_protocol = ld_output EXCEPTIONS no_permission = 1 command_not_found = 2 parameters_too_long = 3 security_risk = 4 wrong_check_call_interface = 5 program_start_error = 6 program_termination_error = 7 x_error = 8 parameter_expected = 9 too_many_parameters = 10 illegal_command = 11 wrong_asynchronous_parameters = 12 cant_enq_tbtco_entry = 13 jobcount_generation_error = 14 OTHERS = 15. IF sy-subrc NE 0. ENDIF.