Passing O/S variables to SQLPLUS

I have a unix environment variable that I want to pass to a SQLPLUS script. How do I do it. If I try to include $VARNAME in the script, it only gets the variable's name, not it's value. For example in a shell script I assign a user name to a variable like this:

export $USRNAM=xyz

In the sqlplus script I want to use that variable in a select like this:

define tbl_owner = $USRNAM
SELECT 'drop table '||owner||'.'||table_name||';'   FROM sys.dba_tables
  WHERE owner = '&&tbl_owner';

But *after* substitution, the WHERE clause contains the variable name, not it's value.

I've also tried running the sql script as "_at_script $USRNAM" and changing the referce from &&tbl_owner to &1, but that does exactly the same thing. It passes the variable's name, not it's value.

--
Chuck Hamilton
chuckh_at_ix.netcom.com

If at first you don't succeed, sky-diving isn't for you.