How to call shell unix command from plsql / sql

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SELECT apps.host_command(‘ls -ltr’) FROM dual;
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SELECT apps.host_command(‘chmod 777 /devel/appl/xxcus/1.0.0/bin/filename’) FROM dual;
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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;

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