stored procedure from oracle to pgsql

Dear,
I'm new in pgsql, come from oracle and sql server.
any one can help by transferring a pl/sql procedure that imports data from a flat file, using UTL_FILE, and inserts or updates tables.
bellow the proc:

CREATE OR REPLACE Procedure UPD is
sOracleMsg varchar2(512);
sCustomerMsg varchar2(100);
fHandle UTL_FILE.FILE_Type;
sPath varchar2(200) := '/home';
sfile varchar2(30) := 'prod_2903.txt';
sBuffer varchar2(4000);
contract vertraege."Vertrags_Nr"%TYPE;
phone vertraege."Phone"%TYPE;
status vertraege."Status"%TYPE;
-- Declare program variables as shown above
BEGIN
fHandle := UTL_FILE.FOPEN(sPath, '/'||sfile, 'r');
IF UTL_FILE.Is_OPEN(fHandle) THEN
loop
begin
UTL_FILE.GET_LINE(fHandle, sBuffer);
phone := substr(sBuffer,1,9);
status := upper(substr(sBuffer,10,1));
contract := substr(sBuffer,10,7);
update vertraege vr
set vr.phone = phone
where vr.vertrags_nr = contract;
commit;
exception
when no_data_found then
insert into vertaraege (phone, vertrags_nr)
values (phone, contract);
commit;
when others then
raise;
end;
end loop;
ELSE
raise_application_error(-20001,'can not open file' || sfile || '. or file not exist');
END IF;
COMMIT;
EXCEPTION
WHEN UTL_FILE.INVALID_PATH THEN
rollback;
raise_application_error(-20002, 'can not open path:' || sPath);
END; -- Procedure

Best Regards / Vriendelijke Groeten / Salutations Distinguées / Freundliche Grüße !!!
Kasem NEFNIFI
AtosOrigin Belgium N.V.
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Email : kasem(dot)nefnifi(at)atosorigin(dot)com <mailto:kasem(dot)nefnifi(at)atosorigin(dot)com>
www.atosorigin.com <http://www.atosorigin.com>
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