Grooming Classroomnotes 10/Mar/2023

Operating Systems and How Applications Work

  • To run any application OS creates a Process.
  • Each Process gets cpu share, Memory and Disk and Network based on the process which you are running.
  • Each Process will have unique identifier (id)

Command Line

  • Every Command is a computer program/Executable
  • Commands have two types of arguments by the way you pass the values
    • positional argument: This argument is processed based on position
      cp 1.txt 2.txt
      cp 3.txt 1.txt
    • keyword argument: In this case around the argument you will pass a name or a keyword. Generally linux style name arguments have two hyphens -- if you pass the keyword an single - if you pass the shorthand notation
      ping -c 2 google.com
      ping google.com -c 2
      ping --count 2 google.com
  • Every command line generally has a documentation which we call as manual. Lets start using manual to figure out what commands can do
  • When you type any command every operating system has a location where the folders to be searched are configured. This is done by a variable (Environmental variable) called as PATH

Approach to work with commands

  • What does the command do.
  • Use --help or man <command>
    Preview
  • Google <command> examples
    Preview

Concept of user and home directory

  • When a user is created in any system a directory called as home directory will be created for the user where he has full permissions
  • Tilde ~ on a terminal represents home directory
Windows:  C:\Users\<username>
Linux:  /home/<username>
Mac: /Users/<username>

  • In command line dot . represents current directory and double dots .. represent parent directory

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devops & cloud enthusiastic learner