What is the home directory?

The home directory is a user-specific directory where personal files, configurations, and scripts are stored. For regular users it is typically /home/username; for the root user it is /root. The tilde ~ is a shell shortcut that expands to the current user's home directory. ~username expands to another user's home. Environment variables $HOME also points to the home directory. Configuration files (dotfiles like .bashrc, .profile, .ssh/) are stored here. Permissions on home directories are typically set to 700 or 750.