getting list of tables from command line

I wrote a little script to individually back up table schemas, table
data and then vacuum the table and it works nicely but I wanted a way to
query a database and get a text file with just the table names and
cannot figure out a way to do that.

my script looks like this...
(all I want is to get a list of the tables into a text file pg_tables)

#/bin/sh
#
DB_NAME=whatever
#
for i in `cat pg_tables`
do
  pg_dump  --username=postgres \
    --schema=db
    --table=$i \
    --schema-only \
    $DB_NAME > schemas/$i.sql
  pg_dump  --username=postgres \
    --schema=db \
    --table=$i \
    --data-only \
    $DB_NAME > data/$i.sql
  vacuumdb --username=postgres \
   --dbname=$DB_NAME \
   --table=db.$i \
   --verbose \
   --full
done

Is there a way to do that?

Craig

PS there's a lack of cohesion between various commands such as vacuumdb
and pg_dump for things like '--schema'