02-VIM

Material ¶

Vim is an acronym for Vi IMproved. It is a free and open-source cross-platform text editor.

Vim comes pre-installed on most *nix operating systems. But if it's not installed on your system, you can install it with a package manager of your choice.
Here's the installation command for based operating systems:
```
sudo apt-get update
sudo apt-get install vim
```
To ensure that it's installed properly, run which vim and you should get /usr/bin/vim in your output.

There are many modes in Vim. But, we'll be looking at the 4 most important modes.

Command Mode
- This is the default mode (also called Normal mode) in Vim.
- Basically, to switch from one mode to another, you have to come to Command Mode first and then navigate to the other mode.
- The commands that you run without any prefix (colon) indicate that you're running the command in command mode.
Command-Line Mode
- You can use this mode to play around with some commands.
- commands in this mode are prefixed with a colon (:).
- You can switch to this mode by pressing : (colon) in command mode.
Insert Mode
- This mode is used to edit the contents of the file.
- You can switch to insert mode by pressing i from command mode.
- You can use the Esc key to switch back to command mode
Visual Mode
- You can switch to this mode by pressing v from the command mode.

run vim to get into Vim
run :edit sample.txt to create a new file
After running that command, you'll be in command mode
To add some text to the created file, press i to insert mode
- In this mode, you can type whatever you want into the file.

To save a file, you have to switch from Insert mode to Command Line mode.
- To switch to Command mode from Insert mode, you have to press the Esc key.
To save the file, use command :W

The proper way to close the file and the Vim editor is by using the command: :q
Alternatively, you can use a command that's the combination of the above 2 commands (save & quit) to quickly save and quit Vim. :wq

Let's open the sample.txt file using vim sample.txt
pressing i from the Command mode will switch to Insert mode.
Type anything you want
Press Esc on the keyboard and type :w to save the file and :q to quit Vim.

To close the file without saving the changes, you have to run :q! from Command mode.

Enter Visual mode by pressing the v key on the keyboard.
Move your cursor, Visual mode highlights the text from the beginning up to your cursor.
hit y to copy the text or hit d to cut the text.
Move the cursor to the place where you want to paste the text.
Press p (in lowercase) to paste the text after the cursor and P (in uppercase) to paste the text before the cursor.
Press :wq to save and close the file

yy: copy current line
- 8yy: copy 8 lines, start from current line
- y$ : copy from the current position to the end of the line
- y^ : copy from the start of the line to the current position
- yw : copy by word (vocabulary)
  - w : jump to next word (start)
  - e : jump tp next word (end)
x (lower case): cut current character (backwards)
- X (upper case) : cut current character (forwards)
dd: delete current line
- 3dd: delete 3 lines, start from current line
u: retrieve previous modification
r(lower case): replace current character
Shift + ^ ： Move to the start of the line
- Shift + $ : Move to the end of the line
gg: Move to the first line
- Shift + H: Move to the first line
- L: Move to the last line
:set nu : show the line number
- set nonu: drop the line number
/[keyword]: search keyword
- n: jump to next search result
:s/[keyword]/[replace keyword]: replace the first matched keyword as second input
- :s/[keyword]/[replace keyword]/g : replace all matched keywords as second input (same line)
- :%s/[keyword]/[replace keyword]/g : replace all matched keywords as second input (whole file)