Basics of VI Editor of Linux

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                       Opening a file     

vi filename: Creating text

Edit modes: These keys enter editing modes and type in the text

of your document.

i     Insert before current cursor position

I     Insert at beginning of current line

a     Insert (append) after current cursor position

A     Append to end of line

r     Replace 1 character

R     Replace mode

<ESC> Terminate insertion or overwrite mode

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                 Deletion of text

x        Delete single character

dd      Delete current line and put in buffer

ndd    Delete n lines (n is a number) and put them in buffer

J        Attaches the next line to the end of the current line (deletes carriage return).

u        Undo last command

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                 CUT AND PASTE

yy      Yank current line into buffer

nyy    Yank n lines into buffer

p        Put the contents of the buffer after the current line

P       Put the contents of the buffer before the current line

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                CURSOR POSITIONING

^d              Page down

^u              Page up

:n               Position cursor at line n

:$               Position cursor at end of file

^g               Display current line number

h,j,k,l          Left,Down,Up, and Right respectively. 

                  Your arrow keys should also work if your keyboard mappings are anywhere near same.

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                STRING SUBSTITUTION

:%s#string1#string2#[g]       Substitute string2 for string1 on lines n1 to n2. If g is included (meaning global), 
                                           all instances of string1 on each line are substituted. If g is not included,only
                                           the first instance per matching line is substituted.

    

    ^ - matches start of line

    . - matches any single character

    $ - matches end of line

These and other "special characters" (like the forward slash) can be "escaped" with \

i.e to match the string "/usr/STRIM100/SOFT" say "\/usr\/STRIM100\/SOFT"

Examples:

:1,$:s/dog/cat/g                   Substitute 'cat' for 'dog', every instance

                                   for the entire file -lines 1 to $ (end of file)

:23,25:/frog/bird/                 Substitute 'bird' for 'frog' on lines

                                   23 through 25. Only the first instance

                                   on each line is substituted.

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              SAVING, QUITTING and other "ex" Commands

These commands are all prefixed by pressing colon (:) and then entered in the lower left corner of the window. They are called "ex" commands because they are commands of the ex text editor - the precursor line editor to the screen editor

vi. You cannot enter an "ex" command when you are in an edit mode (typing text onto the screen)

Press <ESC> to exit from an editing mode.

:w                         Write the current file.

:w new.file             Write the file to the name 'new.file'.

:w!                        Existing.file Overwrite an existing file with the file currently being edited.

:wq                       Write the file and quit.

:q                          Quit.

:q!                         Quit with no changes.

:e filename             Open the file 'filename' for editing.

:set number            Turns on line numbering

:set nonumber        Turns off line numbering

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