# 1 Notes

• Commands preceded with "$" imply that you should execute the command as a general user - not as root. • Commands preceded with "#" imply that you should be working as root with "sudo" • Commands with more specific command lines (e.g. "RTR-GW>" or "mysql>") imply that you are executing commands on remote equipment, or within another program. # 2 Exercises: Editing  vi Cheat Sheet Open: vi filename (fn=filename) vi -r filename Recover a file from a crashed session vi + filename Place the cursor on last line of file. vi +n filename Place the cursor on line "n" of file. vi +/pat filename Place cursor on line with first occurrence of "pat"tern Close: :w Write the file to disk. Don't exit. :w! Write the file to disk even if read/only. :wq Write the file to disk and exit. :wq! Write the file to disk even if read/only and quit. :q Quit the file (only if no changes). :q! Quit the file even if changes. Movement: A Move to end of line, change to insert mode. h Move 1 space backwards (back/left arrow). j Move down 1 line (down arrow). k Move up 1 line (up arrow). l Move 1 space forwards (forward/right arrow) w Move cursor to start of next word. W Same as "w". b Move cursor to start of previous word. B Same as "b". :n Go to line number "n" in the file. Editing: i Enter in to input mode. o Add a line below cursor and enter in to input mode. x Delete character (del key in some cases). D Delete line from right of cursor to end of line. dd Delete entire line. u Undo last edit or restore current line. yy Yank current line. p Put yanked text before the cursor. Searching: /pattern Search for "pattern" in the file going forwards. ?pattern Search for "pattern" in the file going backwards. n Find the next occurrence of pattern found forwards. N Find next occurrence of pattern found backwards. Copy/Cut and Paste <NUM>yyp Copy n lines to buffer, paste below cursor <NUM>yyP Copy n lines to buffer, paste above cursor <NUM>ddp Cut n lines and copy to buffer, paste below cursor <NUM>ddP Cut n lines and copy to buffer, paste above cursor ## 2.1 Practice Using vi '''Remember The vi editor uses "modes"''' The easiest thing to do if you get confused in vi is to press the ESCape key a couple of times and start over with what you were doing. To begin log in or use a terminal with your sysadm user already logged in and do: $ cd
$vi temp.txt vi wil create the file “temp.txt” for you. Press the "i" key to switch to input mode.  Type something like, "VI is great! I think I'll be using vi from now on instead of Word” Press <ENTER> to add lines. Type some more text Save the file that you are in. To do this do: Press the ESCape key for command mode Type “:wq” then hit Enter to save and quit the file (notice the “:” before the “wq”). Copy a large file to your home directory so that you can play around with some more vi commands. We'll copy over your /etc/sysctl.conf file for this exercise. To do this do: $ cd
$cp /etc/sysctl.conf sysctl.conf.bak Edit the file, but let's start at the bottom of the file: $ vi + sysctl.conf.bak 

Go to the first line of the file. Notice the colon (“:”) before the “1”.

:1 <ENTER>

Go to line 10, add a new line, and add in some text:

:10 <ENTER>
Press the “o” key

##
## A sample comment
##

Delete the three lines you just created:

• Move to the first line of new text
• Press the ESCape key
• Press “dd” to delete a line, repeat until the text is gone

Save the file, but don’t exit.

    :w
press <ENTER>

Practice copying and pasting text.

Go to line 12, copy 3 lines of text, go to the bottom of the file, place the text there:

    ESC         (go to command mode)
:12 <ENTER> (go to line 12 of the file)
3yy         (“yank” 3 lines of text and place in copy buffer)
G           (go to the end of the file)
p           (place the contents of the copy buffer here)    

If want to undo this you would type (in command mode):

    u

Go to the top of the file, replace all occurrences of “ipv4” with “ipv6”, but prompt for each change:

    ESC
:1 <ENTER>
:%s/ipv4/ipv6/gc

Say “yes” or “no” to a few prompts then escape from this mode by pressing ctrl-c and .

Go to line 1, search for “kernel”, move to the end of the line, add some text:

    ESC
:1 <ENTER>
/kernel
SHIFT-A
“text here”
ESC

Now let’s exit from the file and not save the few changes we’ve made.

    :q! <ENTER>

## 2.2 Practice, Practice, Practice

As you should be able to see vi is extremely powerful as an editor, but not necessarily intuitive. The best way to get good at using vi is to practice.

Make sure you are logged in as sysadm, then do the following:

$cd$ vi sysctl.conf.bak

In this file practice some of the following items:

• Moving around:
• By word
• End of line
• Start of line
• Top of file
• Bottom of file
• To an absoulte line number
• Copying and pasting multiple lines (use vi commands)
• Copying and pasting single lines (use vi commands)
• Copying and pasting multiple lines (use your mouse buffer)
• Copying and pasting single lines (use your mouse buffer)
• Search for items backwards and forwards

And, anything else you wish to practice.