TP #2 : VIM editor

Principle

To launch the editor, just type vim in a terminal. Unlike usual text editors, vim has 3 modes of operation: interactive mode, insertion mode and command mode:

interactive mode: is the default mode. It is the one you are in when you start vim or when you are in another mode and press the ESC key. In this mode, you can do operations like moving in a file, copying and pasting, deleting text, replacing text…
insertion mode: is the mode that allows you to write text. From the interactive mode, you just have to press the i key to switch to the insertion mode.
command mode: is the mode that allows you to execute vim commands or system commands. From the interactive mode, you have to press the : key and then type the command you want to execute.

First steps

run vim in a terminal
press i to switch to insert mode
type a minimal C program
to save, press ESC (to exit insert mode) and then type :w test.c to save what you have written (: is the command to enter command mode, w is the save -write command and test.c is the file name)
Still in interactive mode, move the file around with the h (left), j ( down), k (up), l (right) keys. You can also use the arrow keys on the keyboard.
To quit vim, just type :q or :q! if you want to force the closure (by default vim does not close if there are unsaved changes).

It is possible to save and exit with the command :wq.

In addition to the h, j, k, l keys, others are useful such as:

0 which automatically returns to the beginning of the current line
$ which allows to go automatically to the end of the current line
gg which allows to go to the first line of the file
G which allows to go to the last line of the file
xG where x is a number allows you to go to the line x
e which goes to the end of the current word
b which goes to the previous word
w which goes to the next word
{ / } goes to the beginning / end of the current paragraph
% goes to the matching brace or parenthesis inside code

Cut / Delete

To delete a character, type x or yx where y is the number of characters to delete
To delete a line, type dd or xdd where x is the number of lines to delete
To delete a word, type dw (delete word) or xdw where x is the number of words to delete
To delete from the beginning of the line to the cursor, type d0.
To delete from the cursor to the end of the line, type d$.

Copy

Same as cut, except the command is yy to copy a line, yw to copy a word, y0 to copy…

Paste

To paste text, type p or xp where x is the number of times to copy. Be careful, the copy is done immediately after the cursor, there is no line break.

Visual Cut / Copy

If you want to cut / copy a specific region of text, you can type v in command mode to enter visual mode and then by using arrows you can highlight the region you want to edit. After that use cut / copy command to go back to command mode.

Replace

To replace a letter, just place the cursor on the line to be replaced and type rs where s is the new letter to be inserted
To replace text, it is possible to use the syntax :s/old/new which replaces the first occurrence of old with new, variants exist:
- :s/old/new/g: replaces all occurrences of the line where the cursor is located
- :#,#s/old/new/g: replaces all occurrences in lines # to # of the file
- :%s/old/new/g: replaces all occurrences in the whole file

Undo changes

To undo a change, type u or xu where x is the number of times to go back

Search for a word

To search for a word after the cursor position, type /word. To go to the next occurrence, type n or N for the previous occurrence
To search for a word before the cursor position, type ?word, the rest is the same

Launch an external command

To do this, just type the name of the command preceded by :!, for example :!ls to display the contents of the current directory

Open another file

In vim just type :e filename to open the file named filename. You can then navigate between files with :e #x where x is the file number.

The configuration file

There are lots of options in vim to make it more user friendly (syntax highlighting, line numbering, aliases…). Here are a few that you can write in a .vimrc file that you put in the root of your home directory (so you don’t have to enable the options every time you open it).

set nocp disables compatibility mode
syn on enables syntax highlighting
set syntax =on enables syntax highlighting
filetype indent plugin on indent according to file type
set nu displays the line number
set showmatch show missing braces / parenthesis
set tabstop =4 tab size in spaces
set shiftwidth =4 size in tab spaces
set softtabstop =4 size in tab spaces
set expandtab turns tabs into spaces
set cursorline highlights the line where the cursor is located
iab #i #include example of an alias, now just type #i then tab and it will be replaced by #include

set nocompatible
filetype off
filetype plugin indent on

set nu
set ai
set si
set mouse=a
set showmatch
set tabstop =4
set shiftwidth =4
set softtabstop =4
set expandtab
set cursorline
set wrap
set textwidth=80
set wrapmargin=2
iab #i #include
iab #d #define

Being efficient with vim

You can enable spelling in vim with the command set spell spelllang=en ( for english or fr for french). When spelling is enables you can jump to the spelling errors with [s (forward jump) ]s (backward jump).
You can correctly indent a whole file by typing gg=G (gg goes to the beginning of the file, = is the indent command and G goes to the end of file)… you can even go back to the line you were with (gg=G’‘).
You can go to any file referred in you source code by typing gf when the cursor is under the file name. When you want to close the visited file you can type bw
You can split the window horizontally resp. vertically with :sp resp. :vsp (and this can be done recursively). Once you have a split window, you can navigate with CTRL w + arrow to navigate and CTRL w + c to close the current split (and even CTRL w + o to close all the split except the active one).
You can easily change the case of text in visual mode: once you have some selected text, press U for uppercase, u for lowercase and ~ to switch case.
For insertion, a insert at the end of the current line, o creates a new blank line after the current one, O creates a new blank line before the current one.

There are many other shortcuts like bookmarks in file, multiple items in the clipboard, repeat the latest insertion command… but it is up to you to find the ones that makes you more efficient and productive in your workflow… bu remember practice is key !

Plugins

vim could be upgraded with many plug-ins that can help for the routine tasks. A popular plug-in manager is Vundle. One installed you can for instance have:

Plugin 'dense-analysis/ale' is a syntax analyzer that highlights on the fly errors in warnings while you are typing. This can helps you to correct many errors before trying to compile your code. By default warning are highlighted with -- while errors are highlighted with >>. The status bar gives some details about the error. Adding `nmap (ale_previous_wrap) nmap (ale_next_wrap)` in your `.vimrc` allows to jump to previous / next errors and warnings with __CTRL + j__ and __CTRL + k__.
Plugin 'scrooloose/nerdtree' allows you to have a sidebar with files in your current folder. If you have the commande nnoremap <Leader>n :NERDTreeToggle<CR> in your .vimrc, you can open / close the file sidebar with the command \n
Plugin 'preservim/nerdcommenter' allows you to (un)comment line(s). For instance \cn comment the current line and \cu uncomment the current line (you can comment / uncomment multiple lines in visual mode.

To install vundle you should:

git clone https://github.com/VundleVim/Vundle.vim.git ~/.vim/bundle/Vundle.vim

then edit your .vimrc file with

set nocp
filetype off
set rtp+=~/.vim/bundle/Vundle.vim
call vundle#begin()
Plugin 'VundleVim/Vundle.vim'               "Packet repository
Plugin 'dense-analysis/ale'                 "Syntax analyzer
Plugin 'scrooloose/nerdtree'                "File manager
Plugin 'preservim/nerdcommenter'            "Comments
call vundle#end()

syn on
set syntax =on
filetype indent plugin on
set nu
set showmatch
set tabstop =4
set shiftwidth =4
set softtabstop =4
set expandtab
set spellsuggest =5
set cursorline

let g:ale_lint_on_insert_leave = 0
nnoremap <Leader>n :NERDTreeToggle<CR>
nmap <silent> <C-k> <Plug>(ale_previous_wrap)
nmap <silent> <C-j> <Plug>(ale_next_wrap)

then inside vim type:

:source % to reload you configuration file
then :PluginInstall

and you should be set-up. If you want to check other plugins, you can visit VimAwesome

Interactive practice

In the terminal, run vimtutor and try to finish the tutorial… have fun :)