When working in CLI there are different modes you can work in. Depending on the mode, you will have specific commands available to you.
This is the mode you begin with when you start a session using Telnet, SSH, or consoled into the switch.
There are only a subset of commands available in this mode.
In privileged exec mode, you have access to all the commands. Usually you will enter a password to get into privileged exec mode.
To make any changes you actually need to move into configuration mode.
In global configuration mode you can make global modifications to the switch. For example, some commands are saving the config, rebooting the switch, changing spanning-tree modes.
Commands used in this mode apply to the whole switch.
This is another configuration mode specifically for configuring VLANs. Pretty straight forward.
This is the configuration mode to make changes to any of the ports on the switch. Again, straight forward.
Here’s the mode where you configure specific lines. An example to get into this config mode is to issue the line vty command.