Cisco IOS Command Cheatsheet

A concise reference of essential Cisco IOS command modes, shortcuts, and core syntax for Packet Tracer learners.

1. IOS Command Modes Hierarchy#

User EXEC Mode
  Prompt: Router>
  Purpose: Basic view-only commands, initial pings.
  Command to enter: (Default upon login)
  Command to advance: enable
       │
       ▼
Privileged EXEC Mode (Enable Mode)
  Prompt: Router#
  Purpose: Diagnostic commands, show running-config, saving, reload.
  Command to enter: enable (from User EXEC)
  Command to advance: configure terminal
       │
       ▼
Global Configuration Mode
  Prompt: Router(config)#
  Purpose: System-wide settings (hostname, banners, static routes).
  Command to enter: configure terminal (from Privileged EXEC)
       │
       ├──► Interface Configuration: interface <type> <number>
       │      Prompt: Router(config-if)#
       │
       ├──► Line Configuration: line console 0 | line vty 0 4
       │      Prompt: Router(config-line)#
       │
       ├──► VLAN Configuration: vlan <id>
       │      Prompt: Switch(config-vlan)#
       │
       └──► Router / Routing Protocol: router ospf <process-id>
              Prompt: Router(config-router)#

2. Essential CLI Shortcuts#

Tab: Auto-completes a partially typed command.
?: Context-sensitive help; shows available commands or next parameters.
Ctrl + A: Jump to the beginning of the current command line.
Ctrl + E: Jump to the end of the current command line.
Ctrl + C or Ctrl + Z: Exit back to Privileged EXEC (Router#).
exit: Move back one level in the mode hierarchy.
end: Immediately return to Privileged EXEC mode from any configuration sub-mode.

3. Basic Device Setup#

Router# configure terminal
Router(config)# hostname R1
R1(config)# enable secret class
R1(config)# banner motd # Authorized Access Only! #
R1(config)# line console 0
R1(config-line)# password cisco
R1(config-line)# login
R1(config-line)# logging synchronous
R1(config-line)# exit
R1(config)# service password-encryption

4. IP Interface Configuration#

R1(config)# interface GigabitEthernet0/0/0
R1(config-if)# description LAN Connection to Switch S1
R1(config-if)# ip address 192.168.1.1 255.255.255.0
R1(config-if)# ipv6 address 2001:db8:acad:1::1/64
R1(config-if)# ipv6 address fe80::1 link-local
R1(config-if)# no shutdown
R1(config-if)# exit

5. Switch SVI and Management#

Switch(config)# interface vlan 1
Switch(config-if)# ip address 192.168.1.2 255.255.255.0
Switch(config-if)# no shutdown
Switch(config-if)# exit
Switch(config)# ip default-gateway 192.168.1.1

6. Saving Configuration#

R1# copy running-config startup-config
Destination filename [startup-config]? [Enter]
Building configuration...
[OK]

! Or the shorter shortcut:
R1# write memory

7. Diagnostic and Verification Commands#

show ip interface brief — Displays operational status and IP of all interfaces.
show ipv6 interface brief — Displays operational status and IPv6 addresses.
show ip route — Displays the IPv4 routing table.
show ipv6 route — Displays the IPv6 routing table.
show running-config — Displays the active configuration in RAM.
show startup-config — Displays the saved configuration in NVRAM.
show interfaces <type> <number> — Detailed interface statistics, duplex, speed, and errors.
show vlan brief — Lists all VLANs and assigned access ports on a switch.
show interfaces trunk — Lists active trunking interfaces, native VLANs, and allowed VLANs.
show etherchannel summary — Lists EtherChannel groups, protocol (LACP/PAgP), and port states.
show mac address-table — Displays dynamically learned and static MAC addresses on a switch.
ping <ip-address> — Tests Layer 3 reachability to a remote host.
traceroute <ip-address> — Identifies the hop-by-hop path taken to reach a destination.