Cisco Help and Editing

Enter ? at any prompt to see a complete listing of available commands that can be used at the prompt level.  You can also do partial a word to see available commands that start with letters before ? (e.g. s?, cl?, eth?).

When entering commands, you don't have to complete the entire word just enough to make it recognizable to the IOS from any other command.  Example: instead of using the show command, you can use sh in place of show and it will work the same.

The ? can also be used to show the next step in the command.  If you type a partial command and press the [Tab] key, the command is completed for you automatically.

    Router_2(config)# int [Tab]
    Router_2(config)# interface
    Router_2(config)# interface ?	
    Async              Async interface
    BVI                Bridge-Group Virtual Interface
    Dialer             Dialer interface
    Ethernet           IEEE 802.3
    Group-Async        Async Group interface
    Lex                Lex interface
    Loopback           Loopback interface
    Null               Null interface
    Port-channel       Ethernet Channel of interfaces
    Serial             Serial
    Tunnel             Tunnel interface
    Virtual-Template   Virtual Template interface
    Virtual-TokenRing  Virtual TokenRing

    Router_2(config)# interface ethernet ?

    <0-0>  Ethernet interface number

    Router_2(config)# interface ethernet 0

Use the [spacebar] to scroll another page if available commands is longer than one page, use the [enter] key to scroll one line at a time.  If help page is scrolled, press any key to return to the command line.

Command Line Editing Commands
Command Meaning
Ctrl+A Moves cursor to beginning of the line.
Ctrl+E Moves cursor to end of line.
Ctrl+B Moves back one character.
Esc+B Moves back one word.
Ctrl+F Moves forward one character.
Esc+F Moves forward one word.
Ctrl+D Deletes a single character at the cursor.
Backspace Deletes a single character.
Ctrl+R Redisplays the command prompt and command line.
Ctrl+U Erases a line.
Ctrl+W Erases a word.
Ctrl+Z Ends Configuration mode and returns to EXEC.
tab Finishes typing a command for you.

Router Command History
Command Meaning
Ctrl+P or Up arrow Shows last command entered.
Ctlr+N or Down arrow Shows previous commands entered.
show history Shows last 10 commands entered by default.
show terminal Shows terminal configurations and history buffer size.
terminal history size [0-256] Changes buffer size (max 256).

To see how long a router has been up, how it was restarted, the IOS version, number of Interfaces, memory, and config-register setting use the command show version from privileged EXEC mode.