Linux Text Editor

 Linux Text Editor:
-------------------
 Windows Text Editor: notepad, notepadd++
 Linux Text Editor: vi/vim, nano, gedit (GUI), emacs, pico

  Most propular/Advanced Text Editor: Vi/Vim
        => vi - old, b&w, default
    => vim - advanced, colorfull (Package must be installed)

 [student@desktopX ~]$ cd
 [student@desktopX ~]$ mkdir linuxY/lesson04 -p
 [student@desktopX ~]$ cd linuxY/lesson04
 [student@desktopX lesson04]$ ls
 [student@desktopX lesson04]$ touch test          ; create new file
 [student@desktopX lesson04]$ cp /etc/passwd  .   ; copy passwd file to cureent dir
 [student@desktopX lesson04]$ ls
  passwd  test

 Working with vi/vim Mode:
 ------------------------
     => insert mode : press "i" or "insert" button
        => exit mode : press "esc" button form keyboard
        => visual mode

 [student@desktopX lesson04]$  vim file1

      => Press "i" for insert mode
      => write something as your requirments ; (Hello world !!)
      => press "esc" button exit from "insert" mode
      => :x         ; save and quit

 [student@desktopX lesson04]$ ls
 [student@desktopX lesson04]$ cat file1
  Hello world !!

 [student@desktopX lesson04]$ vim file1

  => Press "i" for insert mode
  => write "welcome to linux training"
  => press "esc" quit from insert mode
  => :w         ; only save not quit

  => Press "i" for insert mode
  => write "goodbye"

  => :q!        ; quit without save
   
  [student@desktopX lesson04]$ ls
  [student@desktopX lesson04]$ cat file1
  [student@desktopX lesson04]$ vim passwd
   :set nu
     => dd  ; one line delete/cut
     => ndd ; n lines delete/cut
    => dw  ; word delete/cut
    => dl  ; letter delete/cut
    => shift + d ; cut lines from current cursor position

    => yy  ; one line copy
    => nyy ; n lines copy
    => yw  ; word copy
     => yl  ; letter copy
    => 2yl ; 2 letter copy

    => p (Paste)  ; p (below), P(above)

    => shift+g    ; move cursor at last line
    => gg  ; move cursor at 1st line 
    => :25 ; move cursor at 25th line (:25)
    => ctrl + r ; redo
    => u   ; undo
    => o  ; writing (below), O (writing above)
        => /pattern         i.e: /root
        -> n (next)
        -> N (previous)
    => :%s/old_pattern/new_pattern/g ; replace old with new word
    => :%s/old_pattern/new_pattern/gc ; replace old with new word confirmation

  note: all command in "esc" mode

 ======================== Thank you ===================