When working with PostgreSQL, you don't need to install the full database server just to connect to a remote instance. The PostgreSQL client tools package contains all necessary utilities including psql, the command-line interface for PostgreSQL.

On Linux (Debian/Ubuntu)

For Debian-based systems, install the client package with:

sudo apt-get update
sudo apt-get install postgresql-client

On Linux (RHEL/CentOS)

sudo yum install postgresql

On macOS (using Homebrew)

brew install libpq
brew link --force libpq

On Windows

Download the interactive installer from postgresql.org and select only the "Command Line Tools" component during installation.

After installation, verify psql is available:

psql --version

Use the following command to connect from your client machine (Box B) to the server (Box A):

psql -h [server_ip] -p [port] -U [username] -d [database_name]

Parameter	Description
-h	Server hostname or IP address
-p	Port number (default is 5432)
-U	Username for authentication
-d	Database name to connect to

If you encounter connection problems:

1. Verify the server allows remote connections (pg_hba.conf)
2. Check firewall settings on both client and server
3. Ensure the PostgreSQL service is running on the server

For GUI alternatives to psql, consider:

• pgAdmin (official PostgreSQL GUI)
• DBeaver (multi-database GUI tool)
• TablePlus (modern database client)

Instead of typing parameters each time, set these environment variables:

export PGHOST=[server_ip]
export PGPORT=[port]
export PGUSER=[username]
export PGPASSWORD=[password]
export PGDATABASE=[database_name]

Now you can simply run psql without any parameters.

Here's an example of running SQL commands from a script file:

psql -h dbserver.example.com -U admin -f query.sql

Where query.sql contains:

-- query.sql
SELECT * FROM users WHERE active = true;
UPDATE statistics SET last_updated = NOW();

---

When working with PostgreSQL, the server (often called postgres) runs on your database host (Box A in this scenario), while client applications like psql can connect from remote machines (Box B). The key is that you only need the client utilities on Box B to connect to your remote PostgreSQL server.

The PostgreSQL client package contains essential tools including:

• psql: The interactive terminal
• pg_dump/pg_restore: For database backups
• createdb/dropdb: Database management utilities

For Debian-based systems:

sudo apt update
sudo apt install postgresql-client-15

For RedHat-based systems:

sudo yum install postgresql

Download the client-only installer from the official PostgreSQL site:

https://www.postgresql.org/download/windows/

Select only "Command Line Tools" during installation

Using Homebrew:

brew install libpq
brew link --force libpq

Once installed, connect to your remote server:

psql -h box-a.example.com -U username -d database_name

After connecting, run basic commands to verify:

\conninfo  -- Shows connection information
\dt        -- Lists tables
SELECT version(); -- Shows PostgreSQL version

For production environments, consider setting up pgpass for secure authentication:

# ~/.pgpass format
hostname:port:database:username:password

Common problems and solutions:

• Verify pg_hba.conf on the server allows remote connections
• Check if the PostgreSQL port (default 5432) is open
• Ensure the user has login privileges

Other options for connecting to PostgreSQL:

• pgAdmin: GUI administration tool
• DBeaver: Universal database tool
• VS Code extensions: PostgreSQL for VSCode