Procedure call and shell script

Question

When i try to pass a shell variable to a procedure call in a shell script it does not work. But a SQL command ( insert ) has no problem taking the shell variable. Has this something to do with context switch. How to get around this prbokem.
`sqlplus <username/password> -silent << EOF
set serveroutput on size 1000000
exec procA; -- works
exec procB($shell_variable); -- does not work
insert into table1 values ($shell_variable); -- works
EOF`
Thanks!

Answer 1

It works to me :
TEST@db102 SQL> create or replace procedure isnumeric (num in varchar2)
  2  is
  3          a       number;
  4  begin
  5          a := to_number(num);
  6          dbms_output.put_line (num||' is a number');
  7  exception
  8          when others then
  9                  dbms_output.put_line (num||' is NOT a number');
10* end;
11  /
Procedure created.
TEST@db102 SQL> exec isnumeric(123);
123 is a number
PL/SQL procedure successfully completed.
TEST@db102 SQL> exec isnumeric('abc');
abc is NOT a number
PL/SQL procedure successfully completed.
TEST@db102 SQL>
[ora102 work db102]$ cat callvar.sh
export VAR=$1
sqlplus -s test/test << EOF
set serveroutput on size 1000000
exec isnumeric('$VAR');
EOF
[ora102 work db102]$ ./callvar.sh 123
123 is a number
PL/SQL procedure successfully completed.
[ora102 work db102]$ ./callvar.sh abc
abc is NOT a number
PL/SQL procedure successfully completed.
[ora102 work db102]$