One of the most commonly used commands on a switch or router is:
Switch# show version
This command displays information about the currently loaded IOS version, along with hardware and device information. If you are logged into a router or switch remotely, the show version command is an excellent means of quickly finding useful summary information about the particular device to which you are connected. Some of the information points shown from this command are:
- Software version - IOS software version (stored in flash)
- Bootstrap version - Bootstrap version (stored in Boot ROM)
- System up-time - Time since last reboot
- System restart info - Method of restart (e.g., power cycle, crash)
- Software image name - IOS filename stored in flash
- Router type and processor type - Model number and processor type
- Memory type and allocation (shared/main) - Main Processor RAM and Shared Packet I/O buffering
- Software features - Supported protocols/feature sets
- Hardware interfaces - Interfaces available on the device
- Configuration register - Sets bootup specifications, console speed setting, and related parameters
Figure 1 displays the output for a Cisco 1941 ISR, while Figure 2 displays the output for a Cisco 2960 Catalyst switch.