postgresql password from .pgpass

I have a problem connecting to the database.I'm trying to execute pg_dump
command from a user's $HOME (Linux User).
which have a .pgpass.
The .pgpass is like this and his permissions are 600 and belongs to a Linux
User.

localhost:5432:databasename:databaseuser:databaseuser

The command iam executing is $/var/lib/pgsql/bin/pg_dump -U databaseuser
databasename >database.sql
The password's user is plain in the database, put when you try to connect
with this command always require a password

the pg_hba.conf is like this and his permissions are 622 and belongs to
the postgres user.

# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD

local all all
password
host all all 127.0.0.1 255.255.255.255
password
host all all 192.168.0.0 255.255.0.0
password

Please Help me for more details mail me to:

cipriani(at)argentina(dot)com

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