D02

 Introduction to LINUX:

Linux is an operating system, similar to Windows, iOS, and Mac OS. It plays a crucial role in managing hardware resources on computers. Notably, Android, a widely used platform, is built on the Linux OS. The operating system acts as an intermediary, enabling communication between software and hardware, making it essential for software functionality.

▪Most frequent tasks that you perform on PC is creating, moving or deleting Files

▪To manage your files , you  can either use

a. Terminal (Command Line Interface - CLI)

b. File manager (Graphical User Interface –GUI) 

WHY LEARN COMMAND LINE INTERFACE?

• Despite the growing preference for GUI-based systems, the Command Line Interface (CLI) remains highly valuable and extensively utilized in scripting and server administration.
• It offers greater flexibility and a wider range of options compared to GUI. Additionally, powerful features like piping and stdin/stdout are available in CLI but absent in GUI.
• CLI simplifies certain tasks that might require navigating through multiple screens in GUI, condensing them into single commands.
• CLI is resource-efficient, loading quickly and consuming minimal RAM, which becomes significant in resource-intensive situations.

Launching the  cli on ubuntu

Two ways to launch the terminal;

• Go to the Das and type terminal Or 
• we can just press CTRL + ALT + T

Once CLI is launched, we would find something as guru99@VirtualBox(seeimage) written on it.

Tilde '~' signs shows that the user in working in the home directory. If we change the directory the sign will vanish. Like in given second image.

While working as root user '#' is displayed.

• root@VirtualBox:~#

 Present Working Directory 

• The current working directory is the one that you are now viewing.
• Upon booting up, the computer automatically logs on to the home directory.
• We must use the command -pwd (print working directory) to find the directory that we are currently working on.

 Changing Directories 

• 'cd' is the command to use to change the current directory.
• The command cd~ is another option.

Moving to Root Directory

• The '/' symbol in Linux indicates the file system root. Much like Windows' 'c:\'.
• To access the root directory, type 'cd /'. In Windows, we use the backward slash '\', but in UNIX/Linux, we use the forward slash '/'.
• The gap between cd and / must be remembered; else, an error message will appear.

Moving to Root Directory

• Navigate through multiple directories at that same time by specifying its complete path.
• Moving up one directory level:
• for navigating up one directory level, try 'cd ..'

Here we use the 'cd ..' command, where the directory is moved up from 'Pelden' directory to /home.

Relative and Absolute Paths

• There are two paths : 

1. Absolute path and relative path
2. Path in computing is the address of a file or folder 

For example -

• Windows: C:\documentsandsetting\user\downloads
• Linux: /home/user/downloads

Relative Path

• Relative path comes in handy when browsing another sub-directory within a given directory.

Accessing Hardware Information 

• Disk Space Usage :  displays the mounted file system disk usage. Also try out 
• Memory:  display the RAM and Virtual Memory information. You can also use  
• CPU Details:  or  display the information related to CPU.
• Peripheral Component Interconnection(PCI) Devices: , displays the PCI devices list and its information.
• All above information and more can be viewed with the single command  as well.