----------------------------------------------------
-- with just sql.
-- you can save the file as a .sql and execute it..
----------------------------------------------------
mag@itloaner1_local > select count(*) from &table_name;
Enter value for table_name: emp
old   1: select count(*) from &table_name
new   1: select count(*) from emp

  COUNT(*)
----------
        12

mag@itloaner1_local > /
Enter value for table_name: dept
old   1: select count(*) from &table_name
new   1: select count(*) from dept

  COUNT(*)
----------
         4

----------------------------------------------------------------------

----------
-- using pl/sql
----------
mag@itloaner1_local > get sp
  1  create or replace procedure count_tab (tname in all_tables.table_name%type)
  2  is
  3  type rc is ref cursor;
  4  my_rc  rc;
  5  cnt number;
  6  begin      open my_rc for 'select count(*) from ' || tname;
  7     loop
  8             fetch my_rc into cnt;
  9             exit when my_rc%notfound;
 10     end loop;
 11     close my_rc;
 12  dbms_output.put_line('count of records in table '||tname||'        : '||cnt);
 13* end;
mag@itloaner1_local > /

Procedure created.

mag@itloaner1_local > exec count_tab('EMP');
count of records in table EMP   : 12

PL/SQL procedure successfully completed.

mag@itloaner1_local > EXEC count_tab('DEPT');
count of records in table DEPT  : 4

PL/SQL procedure successfully completed.

mag@itloaner1_local >