Configuration mode is a Cisco IOS CLI state for changing device settings. Global configuration mode follows privileged EXEC mode and provides access to feature-specific configuration modes. section 5.2.2
Use the prompt and commands to navigate and work safely:
- Enter global configuration mode with configure terminal from privileged EXEC mode; the prompt changes to hostname(config)#. section 5.2.2
- Configure settings such as the hostname, whose change takes effect immediately and appears in the prompt. section 5.2.2
- Return to privileged EXEC mode with end, exit, Ctrl-C, or Ctrl-Z; exit moves only one level from a deeper configuration mode. section 5.2.3 section 5.2.2
- Use do before a show command when you need operational information without leaving configuration mode. section 5.2.2
Changing a device hostname
Router# configure terminal Router(config)# hostname R1 R1(config)# The hostname changes immediately. To undo it, enter no hostname R1. section 5.2.2
R1(config)# show clock #1
^ #1
% Invalid input detected at '^' marker. #1
R1(config)# do show clock #2
*03:06:22.892 UTC Fri Feb 10 2023 #2
#1 Show commands don’t work in global configuration mode.
#2 Uses do to execute the command in global configuration mode
Compare an invalid show command with do show clock inside global configuration mode. section 5.2.2
