How to execute operating system command from PL/SQL?

There is no direct way to execute operating system commands from PL/SQL. PL/SQL doesn't have a "host" command, as with SQL*Plus, that allows users to call OS commands. Nevertheless, the following workarounds can be used:

1. Database Pipes
-----------------
Write an external program (using one of the precompiler languages, OCI or Perl with Oracle access modules) to act as a listener on a database pipe (SYS.DBMS_PIPE). Your PL/SQL program then put requests to run commands in the pipe, the listener picks it up and run the requests. Results are passed back on a different database pipe.

CREATE OR REPLACE FUNCTION host_command( cmd IN VARCHAR2 )
RETURN INTEGER IS
status NUMBER;
errormsg VARCHAR2(80);
pipe_name VARCHAR2(30);
BEGIN
pipe_name := 'HOST_PIPE';
dbms_pipe.pack_message( cmd );
status := dbms_pipe.send_message(pipe_name);
RETURN status;
END;
/

2. External Procedure Listeners:
---------------------------------
From Oracle 8 one can call external 3GL code in a dynamically linked library (DLL or shared object). One just write a library in C/ C++ to do whatever is required. Defining this C/C++ function to PL/SQL makes it executable. Look at this External Procedure example.

3. Using Java
-------------

4. DBMS_SCHEDULER
-----------------

In Oracle 10g and above, one can execute OS commands via the DBMS_SCHEDULER package. Look at this example:

BEGIN
dbms_scheduler.create_job(job_name => 'myjob',
job_type => 'executable',
job_action => '/d01/oracle/ttt.sh',
enabled => TRUE,
auto_drop => TRUE);
END;
/

exec dbms_scheduler.run_job('myjob');