OpenGeo postgres installation not working from command line but works from PGadminIII on fresh install

Question

Problem:

I just did a default install of opengeo suite (4.1) on Ubuntu 12.04 and followed instructions exactly. The problem is that I can connect just fine to my postgresql through pgadminIII (1.18.1), but I can't connect on command line. Has anyone encountered this and if so, how did you fix?

background:

As I said above, I am installing opengeo suite (4.1) on a 32bit ubuntu 12.04 installation. In fact I did it twice, once at home and once at work and I get the same error so it is repeatable:

Basically, i follow all the instructions on the opengeo website. (http://suite.opengeo.org/opengeo-docs/installation/ubuntu/install.html)

I am sure I am using the 12.04 repository to download software. I changed the postgres.conf and pg_hba.conf to listen on my machine and accept outside connections and use md5 authentication.

I created a password for the postgres user manually like it instructs. However, when it comes time to test the command line, it doesn't authenticate. I get the error:

~$ psql -U postgres -W 
Password for user postgres: 
psql: FATAL:  Peer authentication failed for user "postgres"

The problem is, that I can connect just fine through pgadminIII (1.18.1). I can run the postgis extension and it creates my postgis database. I can even edit files I created in QGIS. But I can't log in via command line so I can't run the shp2pgsql to load any preexisting data. This is a fresh installation on a machine and, as I mentioned, I tried it on two separate machines (both running ubuntu 12.04 x32).

my pga_hb.conf file:

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     peer
# IPv4 local connections:
host    all             all             192.168.0.0/16          md5
# IPv6 local connections:
host    all             all             ::1/128                 md5
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local   replication     postgres                                peer
#host    replication     postgres        127.0.0.1/32            md5
#host    replication     postgres        ::1/128                 md5

Answer 1

You did not change the local line, it's peer mode.

If you want to use md5 auth instead, you must configure md5 auth, e.g.

local   all             all                                     md5

instead of your current:

local   all             all                                     peer

Answer 2

In psql try using -h localhost

psql -h localhost -U postgres -W 

I think psql by default tries to connect on local port (which is using unix sockets) instead of localhost which uses tcpip. I bet your pg_hba.conf is set to only use peer for local and md5 for localhost. So opengeo is using the localhost connection while psql is trying to use the local connection.