32 Chapter 2: Cisco Internetwork Operating System (IOS) Fundamentals
NOTE
One goal of this book is to help you learn more and solidify your understanding of the materials
on the CCNA exam. Hopefully, Table 2-5 will further your understanding. Beware--these
details are covered on the exam questions.
Syslog and Debug
The IOS creates messages when different events occur and, by default, sends them to the
console. These messages are called syslog messages. If you have used the console of a router
for any length of time, you likely have noticed these messages--and when they are frequent,
you probably became a little frustrated.
The debug command is one of the key diagnostic tools for troubleshooting difficult problems
on a router. debug enables monitoring points in the IOS and generates messages that describe
what the IOS is doing and seeing. When any debug command option is enabled, the router
processes the messages with the same logic as other syslog messages. Beware--some debug
options create so many messages that the IOS cannot process them all, possibly crashing the
IOS.
Right-arrow or Ctrl+f
This moves the cursor forward in the currently displayed command
without deleting characters. (The f stands for forward.)
Backspace
This moves the cursor backward in the currently displayed command,
deleting characters.
Ctrl+a
This moves the cursor directly to the first character of the currently
displayed command.
Ctrl+e
This moves the cursor directly to the end of the currently displayed
command.
Esc+b
This moves the cursor back one word in the currently displayed
command.
Esc+f
This moves the cursor forward one word in the currently displayed
command.
Ctl+r
This creates a new command prompt, followed by all the characters
typed since the last command prompt was written. This is particularly
useful if system messages confuse the screen and it is unclear what the
user has typed so far.
Table 2-5
Key Sequences for Command Edit and Recall (Continued)
Keyboard Command
What the User Gets
ch02.fm Page 32 Monday, March 20, 2000 4:57 PM