If you save the configuration, these commands are stored and used when the switch reboots. Using the configuration modes (global, interface, and line), you can make changes to the running configuration. From this mode, you can enter any privileged EXEC command or enter global configuration mode. Normally, you must enter a password to enter privileged EXEC mode. To have access to all commands, you must enter privileged EXEC mode. The user EXEC commands are not saved when the switch reboots. For example, most of the user EXEC commands are one-time commands, such as show commands, which show the current configuration status, and clear commands, which clear counters or interfaces. Only a limited subset of the commands are available in user EXEC mode. When you start a session, you begin in user mode, often called user EXEC mode. You can start a CLI session through a console connection, through Telnet, a SSH, or by using the browser. Enter a question mark (?) at the system prompt to obtain a list of commands available for each command mode.
The commands available to you depend on which mode you are currently in.
The Cisco IOS user interface is divided into many different modes.
