Linux Foundation Classroom Series – 27/Jun/2020

Linux Foundation Series

Linux – The Operating System

  • RedHat Linux, Ubuntu, Centos, SUSE etc are called as distributions.
  • Distribution is Linux + software suite of applications,developer tools
  • In this essence Linux is core of the operating system: kernel

Layers of Abstraction in Linux

  • General Linux System Organization Preview
  • Layers are
    • Hardware
    • Kernel
    • User Process
  • Kernel is in charge for managing
    • Processes
    • Memory
    • Device Drivers
    • System Calls
      • fork
      • exec
  • User Space:
    • Kernel allocates memory for user processes and this is called as userspace. Preview
    • User: A user is an entity that can run processes and own files.

Shell and Terminal

  • when we speak of the commandline we are referring to shell. Shell is a program takes commands and passes them to OS to carry out.
  • Almost all the distributions a shell program called as bash is supplied.
  • To interact with shell we need a terminal

Creating Linux Instances on the cloud

  • Refer Here for setting up the softwares
  • Refer Here for creating a linux ec2 instance in aws
  • Refer Here for creating a linux azure vm
  • Prerequisities
    • Softwares
      • Git Bash
      • Visual Studio Code
    • One free tier cloud account (AWS/Azure)
  • Linux Distributions
    • Ubuntu 18
    • Centos 7
  • Lets create a linux instance and login into that Preview

Standard Input and Standard Output

  • Linux Processes use I/O streams to read and write data.
  • Streams are very flexible, the source of input stream can be a file, device or it can be even the output stream of other process

Linux Commands

  • In the shell prompt we generally execute commands. Lets execute some simple commands


  • Basic command syntax
<command> <args>
echo hello
  • Arguments of two types
    • Positional arguments:
    <command> <arg1> <arg2> ...
    cp 1.txt 2.txt
    • Named arguments
    <command> --<argname> <argumentvalue>
    ping -c 4 
  • ls: this command is used to list the contents of the directory
ls -a

Preview Preview

  • touch: this command creates an empty file
touch 2.txt
  • cp: this command copies files
cp file1 file2
  • mv: this command moves (rename) the files
  • rm
  • echo

Linux directory hierarchy

  • Linux directory Preview
  • / => root directory
  • /bin => Binaries and other executables
  • /etc => system configuration files
  • /home => home directories
  • /opt => optional or third party softwares
  • /tmp => Temporary space
  • /usr => User related programs
  • /var => variable data, log
  • experiment with mkdir, rmdir, less, file, head, tail, exit

Environment and Shell variables

  • Shell variables: Shell can temporarily store variables called as shell variables
To access variable use $
echo $TOPIC
  • Environmental variable: This is also like shell variable, but its not specific to the shell.
export <variable>
  • There is one important environmental variable which is PATH. PATH variable will inform linux to find the commands
echo $PATH

Using Text Editors

  • Every linux generally has a text editor which is vim.
  • To learn using vim please refer here
  • Other editor is nano

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

About learningthoughtsadmin