###Backup without password
If you run the script as **OS user `postgres`** it should not request a password in a standard setup, because password-less `peer` access (or `ident` on older versions) is enabled in [**`pg_hba.conf`**][1] for the postgres user.

So make it a cronjob of postgres if you can. Or enable password-less access for the OS user running the job. You can do that in `pg_hba.conf` but, as @Richard already pointed out, the [password file `.pgpass`][2] file may be a more elegant solution.

###Restore in pgAdmin
I quote the [pgAdmin3 FAQ][3]:

> pgAdmin III uses PostgreSQL's pg_restore tool, which supports only the
> COMRESS and TAR options of pg_dump which is used for backup creation.
> The PLAIN format can't be interpreted by pgAdmin III and pg_restore
> (it can be edited manually, and executed with psql and pgAdmin III's
> query tool in many cases), and thus isn't accepted as valid file.
> 
> We recommend using the COMPRESS format for daily backup tasks. The
> PLAIN format is for advanced manual processing before executing as SQL
> script, and has some restrictions (no blobs) which makes it less
> usable for standard backup tasks.

To restore a plain SQL backup execute it with [psql][4] similar to this:

    psql mydb -p 5432 -U myuser -f backup.sql

For a single database backup you have to connect to the right database. For a cluster-backup with `pg_dumpall`, you might as well connect to the maintenance db "postgres".

You could also load and run such a backup with the pgAdmin query tool. It's plain SQL.


  [1]: http://www.postgresql.org/docs/current/interactive/auth-pg-hba-conf.html
  [2]: http://www.postgresql.org/docs/current/interactive/libpq-pgpass.html
  [3]: http://www.pgadmin.org/pgadmin3/faq/
  [4]: http://www.postgresql.org/docs/current/interactive/app-psql.html