SQL & PL/SQL :: Calling Shell Script Through External Procedure

I am trying to call a shell script through external procedure. To summarize the steps that I followed:

Placed the library file,i.e., the .so file in bin folder of the database server. I have not compiled the .c file and created this. I have taken this from another application.

Then I logged into the sqlplus. Created one library pointing this .so file.

create or replace library ext_proc as '/ngs/app/ivndrptd/bin/execute_cmdlib.so';

After this created the external procedure. This got compiled without any errors.

SQL> create or replace procedure ext_proc_wrapper(in_script IN varchar2)
as external
library ext_proc
NAME "execute_cmd"
parameters (in_script string);
/
Procedure created.

I am trying to execute a script test.ksh which contains a touch command to create a test.txt file.

However irrespective of the procedure running successfully the script is not getting called. I tried several ways of calling the script which are as follows

SQL> exec ext_proc_wrapper('sh /ngs/app/ivndrptd/test.sh');
PL/SQL procedure successfully completed.
SQL>
SQL> exec ext_proc_wrapper('/ngs/app/ivndrptd/test.sh');
PL/SQL procedure successfully completed.
SQL>
SQL> exec ext_proc_wrapper('/ngs/app/ivndrptd/test.ksh');
PL/SQL procedure successfully completed.
SQL>