Using psql variables in scripts

Would like to use variables in combination with files for common psql queries, and am using PG 8.1.4.

For example

\set table_name pg_class

select * from pg_tables where tablename = ‘:table_name’;

This returns no rows, even though the customer table exists.  It appears to be search for a table called ”:table_name”.

I can get this to work by doing the following:

\set table_name '\'pg_class\''

select * from pg_tables where tablename = :table_name;

 schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers

------------+-----------+------------+------------+------------+----------+-------------

 pg_catalog | pg_class  | postgres   |            | t          | f        | f

Is there any way to do use variables within quotes?

Thanks,
Corey Horton