Lesson 2: The Shell and Simple Commands

• Define and describe what a command is
• Describe the general command syntax including options and arguments
• Outline the services of the command-line shell (bash)
• Identify specific characters that have special meaning to the shell
  and define their meaning
• Use the man pages to look up the usage of various UNIX/Linux commands

1. What is Software?
   1. Programs
      1. Instructions
      2. Data
   2. Data files
      1. Text (ASCII)
      2. Binary (data)
   3. Input
      1. Keyboard
      2. Command Line
      3. Files on disk
      4. The kernel
   4. Output
      1. Terminal screen
      2. Files on disk
      3. Another program
2. Command Syntax
   Command [-options...]... [arguments...]
   1. Command
   2. Options
   3. Arguments
3. The Shell
   1. Environment Variables
      1. PATH
      2. TERM
      3. PS1
      4. HOME
   2. Life of the Shell
      1. Prompt the user for a command: $
      2. Read the keyboard for the command line typed by the user.
      3. Parse the command into tokens.
      4. Search for the command.
      5. Execute the command passing along any options and arguments.
      6. Take a nap, until the command is done executing.
      7. Repeat
   3. Special Metacharacters
      1. <cr>
      2. $
      3. double quote (") or single quote (')
      4. ;
      5. \
4. The man Command
   1. Description
   2. Syntax
   3. Options
   4. Environment
   5. Author
   6. Bug Reports
   7. See Also