CS 497C - Introduction to UNIX
Lecture 9: The vi/vim Editor
Chin-Chih Chang chang@cs.twsu.edu

String Search
* vi supports two forms of searches:
* Search for a string or a regular expression in the entire file.
* Search for a single character in the current line.
* Search commands in vi:
 - /str - searches forward for pattern str.
 - ?str - searches backward for pattern str.
 - n - repeats search in the same direction.
 - N - repeats search in the opposite direction.
 - fch - moves cursor forward to first occurrence of character ch in 
   the current line.

String Search
* Fch - moves cursor backward to first occurrence of character ch in 
  the current line.
* tch - moves cursor forward onto but before first occurrence of 
  character ch in the current line.
* Tch - moves cursor backward onto but before first occurrence of 
  character ch in the current line.
* ; - repeats search in the same direction made with f, F, t, or T.
* , - repeats search in a direction opposite to that made with f, F, t, 
  or T.

Searching with Regular Expressions
* vi accepts a generalized pattern containing some special characters 
  (metacharacters) as the search expression. 
* This pattern is called a regular expression and is used to match a 
  group of similar strings.
* The regular expression characters used by vi :

Searching with Regular Expressions
 - * - matches zero or more.occurrences of the previous character
 - [pqr] - matches a single character which is either a p, q, or r.
 - [^pqr] - matches a single character which is not a p, q, or r.
 - . - matches a single character
 - ^pat - matches pattern pat at beginning of line.
 - \<pat - matches pattern pat at beginning of a word.
 - pat\> - matches pattern pat at end of a word.

Search and Replace (:s)
* Search and replace commands in vi :
 - :n1,n2s/s1/s2 - replaces first occurrence of string or regular 
   expression s1 with string s2 in lines n1 to n2.
 - :1,10s/find/look/g - replaces all occurrences of find with look in 
   lines 1 to 10.
 - :.,$s/find/look/gc - interactively replaces find with look from 
   current line through the end.
 - :s - repeats the last substitution on the current line (Linux only).

Handling Multiple Files
* vi uses the Last Line Mode to handle multiple files and buffers.
* These are advanced file handling commands:
 - :r note - reads file note below current line.
 - :r !date - reads output of date between current line.
 - e note - stops editing current fine, and edits file note.
 - e! note - stops editing, but after abandoning changes made to current 
   file.

Handling Multiple Files
 - :e! - loads last saved edition of current file.
 - [Ctrl-^] - returns to most recently edited file.
 - e# - returns to most recently edited file.
 - n - edits next file (when vi is invoked with multiple filenames).
 - rew - rewinds file list to start editing first file (when vi is 
   invoked with multiple filenames).
* You can split the screen into multiple windows in vim.
 - :sp - splits the window.
 - [Ctrl-w][Ctrl-w] - moves between windows.