Which command would you use to save the running configuration to startup configuration?

The command used to save the running configuration to the startup configuration is "copy running-config startup-config." This command is essential in Cisco IOS devices, as it ensures that any changes made to the running configuration are preserved, even after the device is restarted.

When you issue this command, it takes the current running configuration from RAM and copies it into NVRAM (non-volatile RAM), where it is stored permanently. This means that when the device is rebooted, it will load the saved configuration from NVRAM, thus retaining all the settings you have configured.

Understanding this command is crucial for network management. It protects against data loss that could occur if the device is powered off or crashes unexpectedly. Properly saving configurations is a best practice for maintaining network stability and ensuring that the intended configurations persist across reboots.