Cisco IOS CLI Reference
Console Connection
ls /dev/*usb* # Check for TTY port
screen [pasted tty] 9600 # Connect (9600 baud for most Cisco switches)
Use tab completion liberally — it saves typing and helps confirm you're using a valid command.
Privileged Mode & Show Commands
| Command |
Description |
enable |
Enable admin (privileged EXEC) commands |
show interfaces status |
Port connection status, port speed & VLAN assignment |
show ip int brief |
Brief summary of port config status, open/closed, IP assignment |
show vlan |
VLAN summary |
show interface summary |
Traffic summary across ports |
show power inline |
POE assignment |
Configuration Mode
| Command |
Description |
conf t |
Enter configure terminal |
hostname SW01 |
Set switch name to SW01 |
vlan 99 |
Create VLAN 99 |
no vlan 99 |
Delete VLAN 99 |
int fa0/1 |
Configure a single port |
int range g1/0/1-24 |
Configure a range of ports |
Interface Commands
| Command |
Description |
shut |
Disable port |
no shut |
Enable port |
switchport access vlan 99 |
Assign port to VLAN 99 |
power inline never |
Disable POE |
power inline auto |
Enable POE |
Saving & Resetting Config
| Command |
Description |
copy running-config startup-config |
Save current config |
reload |
Reboot and reload config from saved (startup-config) |
erase nvram |
Erase current config and reload factory setup |
erase startup-config |
Similar to erase nvram |
Caution: erase nvram / erase startup-config followed by reload wipes the switch's saved configuration. Confirm you have a backup or are intentionally factory-resetting before running these on a live device. For the full picture — NVRAM vs. flash, the VLAN database gotcha, TFTP backup/restore, and password recovery — see Configuration Management & Recovery.