SAM

• Permission Groups


  • Owner
  • Group
  • All Users
• Permission Types


  • Read
  • Write
  • Execute
• Permission Commands


  • id
  • chmod
  • umask
  • su
  • sudo
  • chown
  • chgrp
  • passwd
• id command


  Displays user identity
• File Types


  • Regular file
  • Directory
  • Symbolic link
  • Character special file
  • Block special file
• File Mode


  Representation of file permissions
• Octal Notation for chmod

  • 000
  • 001
  • 010
  • 011
  • 100
  • 101
  • 110
  • 111
• File Permission Values


  • 777
  • 755
  • 700
  • 666
  • 644
  • 600
• Directory Permission Values


  • 777
  • 755
  • 700
• Symbolic Notation


  • u
  • g
  • o
  • a
• umask command


  Sets the default file permissions
• Setting umask


  1. Binary equivalent (0002)

  2. Binary equivalent (0000)

  3. Binary equivalent (0022)
• su command


  Allows you to temporarily become the superuser
• sudo command


  Allows you to execute a command as another user
• chown command arguments


  • nika
  • nika:users
  • :admins
  • nika:
• chgrp command


  Allows you to change a file's group ownership
• passwd command


  Allows you to change a user's password
• It sets no restrictions on permissions.


  (rwxrwxrwx) 777
• Reasons for Using Text editors in Linux

  • Scripts are written in text editors
  • Many Linux programs use text-based data files for input
  • Many of Linux-operating system services use configuration files that are text-based
• Common Text-Based Editors Used in Linux

  • emacs
  • nano
  • gedit
  • vi
• emacs


  Can be customized and extended with different modes, enabling it to be used like IDE for programming languages such Java or C. It has to be installed first.
• nano


  Is a text editor designed for beginners
• gedit

  Comes with the Gnome desktop. It only runs in the GUI environment.
• vi


  Is a native editor found in all Linux and Unix systems. Most Linux distributions do not include real vi; rather, they include an enhanced replacement called vim (short for vi improved).
• Three (3) Modes of vi Editor

  • command
  • insert
  • replace
• Starting vi


  No steps provided
• Creating a new file

  Confirmation message
• To add text, press the "i" key


  1. To exit insert mode and return to command mode, press Esc

  2. To save the change/s you have made, press the :w command

  3. Confirmation message
• Cursor Movement Commands


  • l or Right arrow (One character to the right)
  • h or Left arrow (One character to the left)
  • j or Down arrow (One line down)
  • k or Up arrow (One line up)
  • 0 (To the beginning of the current line)
  • ^ (To the first non-whitespace character on the current line)
  • $ (To the end of the current line)
  • w (To the beginning of the next word or punctuation character)
  • W (To the beginning of the next word, ignoring punctuation characters)
  • Ctrl+f or Page Down (One page down)
  • Ctrl+b or Page Up (One page up)
  • numberG (To line number)
  • G (To the last line of the file)
• To append text to an existing file, use the A command


  The A command moves the cursor to the end of the line before starting insert mode.
• To insert a blank line between two (2) existing lines

  1. Use the o command to insert the line below the current line

  2. Use the O command to insert the line above the current line
• Text Deletion Commands


  • x (The current character)
  • 3x (The current character and the next two (2) characters)
  • dd (The current line)
  • 5dd (The current line and the next four lines)
  • dW (From the current cursor position to the beginning of the next word)
  • d$ (From the current cursor location to the end of the current line)
  • d0 (From the current cursor location to the beginning of the line)
  • d^ (From the current cursor location to the first non-whitespace character in the line)
  • dG (From the current line to the end of the file)
  • d20G (From the current line to the twentieth line of the file)
• Text Yanking/Pasting Commands


  • yy (The current line)
  • 5yy (The current line and the next four lines)
  • yW (From the current cursor position to the beginning of the next word)
  • y$ (From the current cursor location to the end of the current line)
  • y0 (From the current cursor location to the beginning of the line)
  • y^ (From the current cursor location to the first non-whitespace character in the line)
  • yG (From the current line to the end of the file)
  • y20G (From the current line to the twentieth line of the file)
• Productivity Software


  • It enables users to work with documents and files such as: word-processed documents, spreadsheets, presentation graphics documents, database relations, graphic images
• LibreOffice


  The office suite for Linux. It includes: Writer (word processing), Calc (spreadsheet), Impress (presentation), Draw (vector graphics and flowcharts), Base (database), Math (formula editing)
• Writer (word processing)


  • It has AutoComplete feature, which can suggest commonly-used words and phrases to complete what you have started typing, using the built-in dictionary and by scanning the documents you open.
• Calc (spreadsheet)


  • It has Advanced DataPilot technology that makes it easy to pull in raw data from corporate databases, and then cross-tabulate, summarize, and convert it into meaningful information. Real-time data streams can now be integrated in sheets and reports, and factored in calculations.
• Impress (presentation)


  • It has the Fontworks tool that lets you create attractive 2D and 3D images from text. It supports multiple monitors, and its bundled Presenter Console extensions allows you more control over your slide show, such as the ability to see the upcoming slide, view slide notes, and control the presentation timer while the audience is looking at the current slide.
• Draw (vector graphics and flowcharts)

  • It is an excellent package for producing technical drawings, brochures, posters, and many other documents. It lets you manipulate graphical objects, group them, crop them, use objects in 3D, and much more.
• Base (database)


  • It provides native-support drivers from some of the most widely employed multi-user database engines: MySQL/MariaDB, Adabas D, MS Access, PostgreSQL