When managing PostgreSQL installations on Ubuntu, many administrators encounter a puzzling situation - the initdb command appears in documentation but seems missing from their system. This isn't actually a missing package issue, but rather a matter of understanding Ubuntu's PostgreSQL package structure.

The initdb binary is typically located in one of these paths on Ubuntu systems:

/usr/lib/postgresql/<version>/bin/initdb
/usr/local/pgsql/bin/initdb

For PostgreSQL 14 on Ubuntu 20.04 for example:

/usr/lib/postgresql/14/bin/initdb

Instead of directly calling initdb, Ubuntu recommends using pg_createcluster for management:

sudo pg_dropcluster --stop 14 main
sudo pg_createcluster 14 main

This properly handles Ubuntu's init script integration and configuration files.

For a full database reset including user permissions:

# Stop PostgreSQL service
sudo service postgresql stop

# Remove existing cluster
sudo pg_dropcluster --stop 14 main

# Create fresh cluster
sudo pg_createcluster 14 main --start

# Verify status
sudo pg_lsclusters

If you need to use initdb directly (not recommended for production):

sudo -u postgres /usr/lib/postgresql/14/bin/initdb \
-D /var/lib/postgresql/14/main \
--encoding=UTF8 \
--locale=en_US.UTF-8

Many Ubuntu users encounter confusion when trying to reset their PostgreSQL database to its initial state. While initdb is indeed the standard tool for this purpose, its location isn't always intuitive in Ubuntu's packaging structure.

On Ubuntu systems, initdb is typically installed with the postgresql-common package. The exact path varies by PostgreSQL version:

# For PostgreSQL 14:
/usr/lib/postgresql/14/bin/initdb

# For PostgreSQL 12: 
/usr/lib/postgresql/12/bin/initdb

Here's a complete workflow to properly reset your PostgreSQL database:

# Stop PostgreSQL service
sudo service postgresql stop

# Remove existing data directory (backup first if needed)
sudo rm -rf /var/lib/postgresql/14/main/

# Reinitialize with initdb
sudo -u postgres /usr/lib/postgresql/14/bin/initdb -D /var/lib/postgresql/14/main/

# Restart service
sudo service postgresql start

Ubuntu provides pg_createcluster as a more system-integrated way to handle this:

# Remove existing cluster
sudo pg_dropcluster 14 main --stop

# Create fresh cluster
sudo pg_createcluster 14 main

# Start the new cluster
sudo service postgresql start

Before performing a reset:

• Backup all important data using pg_dump
• Verify the PostgreSQL version you're working with
• Check available disk space for the new database

If you encounter permission problems, ensure you're running commands as the postgres user. For missing directories, check that the PostgreSQL package is properly installed.

# Verify installation
dpkg -l | grep postgresql