Linux Vi Editor: Modes, Create File, Save, Movement

• Linux text editors are used for scripts, text-based data files, and configuration files
• Common text-based editors include emacs, nano, gedit, and vi
  • Emacs: an editor used as an IDE for programming languages like Java or C, needs to be installed
  • Nano: beginner-friendly text editor
  • Gedit: comes with Gnome desktop and can only run on GUI environment
  • Vi: native editor in ALL LINUX SYSTEM

Vi Editor Modes

• Command mode: keystrokes operate as commands
• Insert mode: entered characters are placed at the current cursor position
• Replace mode: replaces the character at the current cursor position

Creating a New File in Vi

• To create a new file: use vi sample.txt, this will give a confirmation message
• To insert: use i
• To exit: use esc

Vi Save Command

• :w saves the file

Cursor Movement Commands

• l or Right arrow: moves one character to the right
• h or Left arrow: moves one character to the left
• j or Down arrow: moves one line down
• k or Up arrow: moves one line up
• 0: moves to the beginning of the current line
• ^: moves to the first non-whitespace character on the current line
• $: moves to the end of the current line
• w: moves to the beginning of the next word or punctuation character
• W: moves to the beginning of the next word, ignoring punctuation characters
• Ctrl+f or Page Down: moves one page down
• Ctrl+b or Page Up: moves one page up
• numberG: moves to line number, such as 1G to the first line
• G: moves to the last line of the file

Vi Editor Insert Commands

• "A" moves the cursor to the end of the line before starting insert mode
• "o" inserts a blank line on 2 existing lines below the current line
• "O" inserts a blank line above the current line

Text Deletion Commands

• x: Deletes the current character
• 3x: Deletes the current character and the next two characters
• dd: Deletes the current line
• 5dd: Deletes the current line and the next four lines
• dw: Deletes from the current cursor position to the beginning of the next word
• d$: Deletes from the current cursor location to the end of the current line
• de: Deletes from the current cursor location to the beginning of the line
• d^: Deletes from the current cursor location to the first non-whitespace character in the line
• dG: Deletes from the current line to the end of the file
• d20G: Deletes from the current line to the twentieth line of the file

Yanking/Pasting Commands

• yy: Copies the current line
• 5yy: Copies the current line and the next four lines
• yw: Copies from the current cursor position to the beginning of the next word
• y$: Copies from the current cursor location to the end of the current line
• y0: Copies from the current cursor location to the beginning of the line
• y^: Copies from the current cursor location to the first non-whitespace character in the line
• yG: Copies from the current line to the end of the file
• y20G: Copies from the current line to the twentieth line of the file

Productivity Software

• Productivity software enables users to work with documents such as word-processed documents, spreadsheets, presentation graphic documents, database relations and graphic images
• LibreOffice is an office suite for Linux similar to Microsoft Office
  • Writer: word processing
  • Calc: spreadsheet
  • Impress: presentation
  • Draw: vector graphics and flowcharts
  • Base: database
  • Math: formula editing
• Other software includes: GIMP, MySQL/MariaDB, Adabas D, MS Access, and PostgreSQL

Permissions Overview

• Permissions determine access rights in a system
• Groups:
  • Owner: Only the owner has certain permissions
  • Group: A selected group has certain permissions
  • All User: Everyone on the system has certain permissions
• Permission Types:
  • Read: Allows viewing only
  • Write: Allows editing
  • Execute: Allows running

Permission Commands

• id: displays the user identity
• chmod: modifies access rights of a file/directory
• umask: sets default file permissions
• su: allows temporary superuser access. Requires password of superuser
• sudo: executes a command as another user, uses current user's password
• chown: changes a file's ownership
• chgrp: changes a file's group ownership
• passwd: changes a user's password

Common Linux File Types

• Ordinary or regular file
• d: Directory
• l: Symbolic link
• c: Character special file
• b: Block special file

File Permission Notation

• File permissions are displayed in the format rwx, where:
  • r stands for read
  • w stands for write
  • x stands for execute
• The permissions are categorized by Owner, Group, and World
• Values for permissions:
  • 1 - execute
  • 2 - write
  • 4 - read
• Permissions can be transcribed as rwx=777, r-w=702, --x=001

Symbolic Notation

• u+x: Allows execute permission for the owner
• u-x: Removes execute permission from the owner
• +X: Allows execute permission for the owner, group, and everyone else
• o-rw: Removes read and write permission from anyone besides the owner and group owner
• go=rw: Sets the group owner and anyone besides the owner to have read and write permission and removes execute permissions from the group owner and others
• u+x, go=rx: Adds execute permission for the owner and sets the permissions for the group and others to read and execute
• su: Switch user
• sudo: Superuser do