VI Editor

Save a file in vi without sudo

:w !sudo tee %

Input/Append text VI

• a - Append after the cursor
• i - Append before the cursor
• I - Append at the beginning of a line
• A - Append at the end of a line
• o - Create new line under the cursor
• O - Create new line above the cursor

Cursor Movement in VI

• gg Begning of the file
• G Move to the last line in the file
• 5GMove to line 5 of the file (5 can be any line number)
• H Upper left corner (home) of the current screen
• M Middle line
• L Lower left corner
• ^ Beginning of line
• $ End of line
• l Forward a character
• w One word forward
• b Back one word

Vi Commands

• u Undo last change
• U Undo all changes on line
• :w !sudo tee % Save a file that is opened without sudo
• dd Delete current line
• ndd Delete n lines of buffer
• %d Delete all lines in a file

Search and Replace

Syntax: :[address]s/old_text/new_text/

• :%s/foo/bar/g Replace foo with bar globally
• :s/foo/bar/g replace all matches (g flag) of 'foo' with 'bar' on the current line only
• :%s/foo/bar/gc Replace foo with bar but confirm for every change
• :s/foo/bar/ replace the first match of 'foo' with 'bar' on the current line only

Address components

Address	Description
.	Current line
n	Line number
$	Last line
n.+m	Current line plus m lines
/string/	A line that contains "string"
%	Entire file
[addr1],[addr2]	Specifies a range

VI Commands

• :set number Show line numbers
• :set list Show invisible characters