The shell prompt is a symbol or a string of characters that indicates the shell is ready to accept commands. The shell prompt can be customized by the user or by the system administrator. The default shell prompt for a normal user is usually a dollar sign ($), while the default shell prompt for the root user is usually a hash sign (#). The root user is the superuser or the administrator of the system, who has full access and control over all files, commands, and resources. Running commands as root can be dangerous, as it can cause irreversible damage to the system if done incorrectly. Therefore, it is advisable to use sudo or su to run commands as root only when necessary, and to switch back to a normal user as soon as possible. The shell prompt indicates the shell is running with root privileges when it ends with a hash sign (#). References:

Linux Essentials - Linux Professional Institute (LPI)

Running a shell command as root - Unix & Linux Stack Exchange