Introduction

vi (short for “visual editor”) is a text editor that is widely used in Unix-like operating systems. It is a terminal-based editor, which means it can be used from a command-line interface. vi is known for its mode-based interface and for being able to perform advanced text editing tasks efficiently.

There are two main modes in vi:

Command mode: The mode you start in when you first open a file in vi. In this mode, you can execute commands to perform actions such as saving changes, quitting the editor, or moving the cursor.
Insert mode: The mode you enter when you want to insert text into a file. In this mode, you can type text normally, as if you were using a word processor.

To switch from Command mode to Insert mode, you can press the i key. To switch back to Command mode, you can press the Esc key.

Here are some basic commands you can use in vi:

i: Enter Insert mode.
Esc: Return to Command mode.
:w: Save changes to the file.
:q: Quit vi without saving changes.
:wq: Save changes and quit vi.
:x: Save changes and quit vi (same as :wq).
dd: Delete the current line.
x: Delete the character under the cursor.
u: Undo the last change.
/pattern: Search for the pattern in the file.

Note that the commands in vi must be entered in Command mode

Commands that I used

Auto-complete the words

CTRL + p

Substitute with ascending numbers:

Suppose we want to replace each occurrence of “abc” with “xyz_N” where N is an ascending number (xyz_1, xyz_2, xyz_3, and so on). One approach uses the following command:
```
:let i=1 | g/abc/s//\='xyz_'.i/ | let i=i+1
```
This will replace only first occurrence of each line. There is also command that can replace all, for it look at link below.

Ref: http://vim.wikia.com/wiki/Making_a_list_of_numbers

Comment all lines contaning a pattern:

        :%s/.*pattern/#&

This command adds # to the begining of each line contaning pattern.

Ref: https://stackoverflow.com/questions/19529278/how-do-i-comment-all-lines-that-match-a-search-pattern-in-vim

To insert a file immediately after the line containing the cursor:

:r examples.txt

This inserts the contents of the file examples.txt immediately after the current line.

To insert the contents of another file after a specific line in the current file:

    23:r toc.txt

This inserts the contents of the file “toc.txt” after line 23 of the current file. Line 24 is empty; the contents of the inserted file begin at line 25. 3. kk

vi cheatsheet link

search a keyword

press Esc key to go to command mode, then type

    /keyword

then press enter. And use key “n” to search next and use “shift/Caps Lock button” to search in reverse direction

Search and replace:

go in command mode by pressing Esc key, then type

    :%s/wordToBeReplaced/NewWord/gc

then press enter. Then if you want to change the highlighted word then use “y” else use “n” to go to next word.

Several different options for search and replace

:s/foo/bar/g

Change each ‘foo’ to ‘bar’ in the current line.
:%s/foo/bar/g

Change each ‘foo’ to ‘bar’ in all the lines.
:5,12s/foo/bar/g

Change each ‘foo’ to ‘bar’ for all lines from line 5 to line 12 (inclusive).
:'a,'bs/foo/bar/g

Change each ‘foo’ to ‘bar’ for all lines from mark a to mark b inclusive.
:'<,'>s/foo/bar/g

When compiled with, +visual change each ‘foo’ to ‘bar’ for all lines within a visual selection. Vim automatically appends the visual selection range (‘<,’>) for any ex command when you select an area and enter
:.,$s/foo/bar/g

Change each ‘foo’ to ‘bar’ for all lines from the current line (.) to the last line ($) inclusive.
:.,+2s/foo/bar/g

Change each ‘foo’ to ‘bar’ for the current line (.) and the two next lines (+2).
:g/^baz/s/foo/bar/g

Change each ‘foo’ to ‘bar’ in each line starting with ‘baz’.

Ref: http://vim.wikia.com/wiki/Search_and_replace

Inserting text in multiple lines (Visual Selection)

Press Ctrl+V
Extend the visual block using jj or arrow
Press $ for the end of line press ^ for beginning of line.
Press A or Shift+i for insert mode
Then type anything that you want
Then press ESC.

Ref: http://vim.wikia.com/wiki/Inserting_text_in_multiple_lines

Search and Replace using Visual Selection

Press Ctrl+V
Extend the visual block using jj or arrow
when text is selected visually, press : to enter the command (when you press : then :’<,’> will automatically come)
example of the command:

s/red/green/g

Ref: http://vim.wikia.com/wiki/Search_and_replace_in_a_visual_selection

Mark Option in Vi:

mx => mark the current line with letter x (where x is from a to z or A to Z)

‘x => Find line marked with letter x

Usual commands like d, y, etc also work with mark option.

For detail look at ref: http://vim.wikia.com/wiki/Using_marks

Delete some characters from the end of many lines:

To delete 6 characters from the end of all line, use command:

       :%s/.\{6}$//

To list the line numbers from present line to end

       :%s/.\{1}$/\=printf('%-4d', line('.'))

How to use Recorder?

An example to replace string OldString with NewString contained in multiple *.cpp files:

vim *.cpp
qx # start recording to register x
:%s/OldString/NewString/g
:wnext
q # stop recording
@x # playback to see if it works correctly
999@x # repeat 999 times to complete the job

Ref: http://vim.wikia.com/wiki/Recording_keys_for_repeated_jobs -> tutorial on record: http://www.thegeekstuff.com/2009/01/vi-and-vim-macro-tutorial-how-to-record-and-play/

How to edit record:

Assume that we are using register a for recording a task.

You can use “ap which will insert the text in the buffer (where a is your register):

        iThis is A<1b>

Now I can just change the line to maybe:

```bash
    iThis is an edited macro<1b>
```

Then I do ^v$"ay to yank (copy) this line to the a register:

        ^ for start of line
        v for visual mode
        $ for end of line
        "ay yank the selection to register a

Reference: https://vi.stackexchange.com/questions/759/how-can-i-view-and-edit-my-recording-i-e-recorded-macro

Efficient way to remove multiple spaces between two words

ciw and then escape back to normal mode.

duplicate lines matching a pattern, and modify the second line, all in one command

TASK: Search all lines containing “atributeA”, like this one

this.attributeA=attributeA //basic constructor

should turn into

this.attributeA=attributeA //basic constructor
this.attributeB=attributeB //basic constructor

Soulution

:g/attributeA/ copy . | s//attributeB/g

where

:g/pattern/ command1 | command2 | ...

executes commands on each line matching pattern (see :help :global).

Here,

copy .

copies the current line (see :help :copy) matched by :g to after the address .` (meaning the current line), and

s/pattern/replacement/g

then performs a substitution on the current line (see :help :substitute), i.e. the copy you just made. The g flag at the end causes the substitution to be performed for all matching patterns in the line, not just the first. Also note that I left the search pattern empty: Vim will remember the last search pattern used in the previous :global or :substitute command as a convenience.

Reference: https://stackoverflow.com/a/29369960/2302094

Some other commands

Insert output of command in vi-editor: :.! date
Increment a number : Ctrl-a
Decrement a number : Ctrl-x
Cursor movement: Put cursor to first line of screen : H
Cursor movement: Put cursor to last line of screen : L
Cursor movement: Put cursor to middle line of screen : M
Delete command: di( delete all character within parentheses
Delete command: di" delete all character within quotes
Toggle case of letter: ~
Toggle case of current line: g~~
Toggle case of all character from the cursor position to the end of line: ` g~$`
Change case of current line to Upper case: gUU
Change case of current line to lower case: guu
Go to end of word: w
- Option e moves us to last letter of the word
vim options:
```
  -i  : ignore case
```
Run a command to place output in current line
```
  :r !command
```
Delete all empty lines ( Ref )
```
  :g/^$/d
```
Delete all empty lines or remove all lines containing only white spaces ( Ref )
```
  :g/^\s*$/d
```

Run Commands From Vi Editor: :! ls Insert output of the command in vi-editor: :.! date Run a command to place output in current line :r !command Increment a number : Ctrl-a Decrement a number : Ctrl-x Cursor movement: Put cursor to the first line of screen : H Cursor movement: Put cursor to the last line of screen : L Cursor movement: Put cursor to middle line of screen : M Delete command: di( delete all character within parentheses Delete command: di” delete all character within quotes Toggle case of the letter: ~ Toggle case of current line: g~~ Toggle case of all character from the cursor position to the end of line: g~$ Change case of the current line to Uppercase: gUU Change case of the current line to lowercase: guu vim options:

-i : ignore case Delete all empty lines ( Ref ) :g/^$/d Delete all empty lines or remove all lines containing only white spaces ( Ref ) :g/^\s*$/d Substitute with ascending numbers: => Suppose we want to replace each occurrence of “abc” with “xyz_N” where N is an ascending number (xyz_1, xyz_2, xyz_3, and so on). One approach uses the following command:

:let i=1

g/abc/s//=‘xyz_‘.i/

let i=i+1

This will replace the only first occurrence of each line. There is also command that can replace all, for it looks at the link below. Ref: http://vim.wikia.com/wiki/Making_a_list_of_numbers

Sort lines = > :%sort

Vi-Editor

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