What command is used to find the IOS version and software used on a Cisco device?

The command used to find the IOS version and software running on a Cisco device is "show version." This command provides detailed information about the device’s internals, including not only the IOS version but also system hardware, memory and processor details, and the system uptime. It's a fundamental command for network administrators when diagnosing issues or verifying the readiness of a device for configuration changes or updates.

In contrast, the other options do not serve this specific purpose. For instance, the command "show running-config" displays the current configuration of the device, which focuses on the active settings rather than the software's version. "Display version" is not a recognized command in Cisco IOS syntax, as Cisco devices use "show" for command syntax. Lastly, "version status" is also not a valid command in Cisco IOS, further highlighting the uniqueness of "show version" in providing the necessary information about the IOS version and software in use.