psql command not responding - linux

Question

When I run the psql command just by itself (no arguments, postgres-10 installed, running from Debian Sid), it just stays blank and runs forever.
I tried checking the status with systemctl status postgresql and it says the server is active. It does the same when I run it by specifying the host as localhost.
This is the connection settings section of my postgresql.conf file:
listen_addresses = '*' # what IP address(es) to listen on;
# comma-separated list of addresses;
# defaults to 'localhost'; use '*' for all
# (change requires restart)
port = 5432 # (change requires restart)
max_connections = 100 # (change requires restart)
# Note: Increasing max_connections costs ~400 bytes of shared memory per
# connection slot, plus lock space (see max_locks_per_transaction).
#superuser_reserved_connections = 3 # (change requires restart)
unix_socket_directories = '/var/run/postgresql' # comma-separated list of directories
# (change requires restart)
#unix_socket_group = '' # (change requires restart)
#unix_socket_permissions = 0777 # begin with 0 to use octal notation
# (change requires restart)
#bonjour = off # advertise server via Bonjour
# (change requires restart)
#bonjour = on # MJB
#bonjour_name = '' # defaults to the computer name
# (change requires restart)
# - Security and Authentication -
#authentication_timeout = 1min # 1s-600s
ssl = true # (change requires restart)
#ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL' # allowed SSL ciphers
# (change requires restart)
#ssl_prefer_server_ciphers = on # (change requires restart)
#ssl_ecdh_curve = 'prime256v1' # (change requires restart)
#ssl_renegotiation_limit = 512MB # amount of data between renegotiations
ssl_cert_file = '/etc/ssl/certs/ssl-cert-snakeoil.pem' # (change requires restart)
ssl_key_file = '/etc/ssl/private/ssl-cert-snakeoil.key' # (change requires restart)
#ssl_ca_file = '' # (change requires restart)
#ssl_crl_file = '' # (change requires restart)
#password_encryption = on
#db_user_namespace = off
# GSSAPI using Kerberos
#krb_server_keyfile = ''
#krb_caseins_users = off
# - TCP Keepalives -
# see "man 7 tcp" for details
#tcp_keepalives_idle = 0 # TCP_KEEPIDLE, in seconds;
# 0 selects the system default
#tcp_keepalives_interval = 0 # TCP_KEEPINTVL, in seconds;
# 0 selects the system default
#tcp_keepalives_count = 0 # TCP_KEEPCNT;
# 0 selects the system default
Where are the places I should look in order to address this problem?

Answer 1

So we probably need a bit more information. Are you dropping to a terminal and running psql? And if so, are you running JUST psql with no arguments (ie $ psql <enter>?
When you run the psql command by itself, it will try to connect to a Postgres server on a socket or at 127.0.0.1. If it's hanging, it's probably trying to connect to the 127.0.0.1 and either the firewall is dropping packets or there's nothing responding, causing it to hang. If you wait long enough, it should time out.
Maybe a better question is "what are you expecting to happen?" Is there a Postgres server running on the same machine as the terminal? Are you sure it's running? Is it installed a service? If so, does sudo systemctl status postgresql-10 indicate that it's running? What happens if you run psql -h 127.0.0.1? Is Postgres configured to listen on a network interface? Is there a firewall blocking port 5432? Is Postgres running on port 5432?
...And the list of potential questions goes on. Try to nail down some answers to the question above. Your question is the SO equivalent of "my car doesn't work- what's wrong?"; we need some more information in order to help you out. :)