Fundamental of Programming

                                                                                    Process A process in Linux is a running program/ an instance program that is being executed by the Linux kernel. Types of Linux Processes 1. Foreground Processes 2. Background Processes Foreground processes: A process that requires the user to start it using a terminal command on Program. It requires an input trigger from a user, so every foreground process is manually triggered. Background Processes:  A process that runs independently on user input. It can run multiple processes at the same time in a background process.                                              ...

  Linux filesystem is used to handle the data management of the story. It manages the filename, file size, creation date and much more information about a file. The basic purpose of a filesystem is to represent and organize the system's storage resources. Pathnames It is a text string made up of one or more names separated by forward slashes. It indicates how to find something in the hierarchical file system tree. some examples: /home, /etc/passwd, etc...  / is also known as root directory. Example of relative path $pwd /home/kt $cd abc $pwd /home/kt/abc Example of absolute path $pwd /home/kt $cd /home/kt/abc $pwd /home/kt/abc File types in Linux: Regular or ordinary files:  stores data of various content types such as text, audio, video, images, scripts, and programs. Directories: It is a binary file used to track and locate other files and directories. Special files: Character device and block device file: Exposes device as a file in the file system. A special file prov...

  Linux commands: Listing files(ls): to see the list of files on UNIX or Linux system. Ls- R: shows all the files not only in directories but also sub directories. Ls -al - gives detailed information of the files. ls - a - command to view hidden files. Creating and viewing files: cat - commands is used to display text files. It is also used for copying, combining and creating new text files. cat filename - to view the file created. Deleting files Cat command - It will only show a message when something goes wrong or when an error has occurred.  cat sample - to view the new combo file "sample". rm - removes files from the system without confirmation. mv - to move a file to different directory. The command needs super user/ root user permission. Currently the command is executed as a standard user. sudo - used to overcome error. sudo program allows regular users to run programs with the security privileges of the super user or root user. Moving and renaming files: sudo command ...

 An operating system is software that manages all of the hardware resources associated with desktop or laptop. Two ways to manage files: Terminal (Command Line Interface - CLI) File Manager (Graphical User Interface - GUI) Why learn Command Line Interface? Granular control of an OS or application. More efficient management of a large number of systems. Ability to store scripts to automate regular task. Enables troubleshooting of network connection issues or resolving other system tasks. ':' - It is a simple seperator. '~' - It shows that the user working in the home directory.  '$' - It suggests that you are working as a regular user in Linux. '#' - Sign for root user. Present Working Directory. Directory which is currently browsing. pwd - Command which determines the directory you are presently working on. It stands for print working directory. Changing root directories. cd - Changes current directory. cd/ cd~ - to navigate to home directory. Moving to ...

  Containers It is a standard package of software that packages the code and all its dependencies so that the application runs quickly and reliably from one computing environment to another. It allows application deployment to be packaged lightly and immutably.  Linux Containers It is a set of one or more processors isolated from the rest of the system. Why use Linux Containers? They enable effiency in resource usage, ease of deployment and scalability. They are essential for real time data streaming with Apache Kafka. They make it easy to move contained application between environments while retaining full functionality. Containers vs Virtualization Virtualization: The stream able package is a virtual machine. Includes a complete operating system as well as application. Containers: Runs a single operating system. All containers share the operating system kernel. Benefits of Containers Agility and Productivity: Allows applications to be more rapidly deployed, patched or scaled...

 Application layer Provides protocols that allow software to send and receive information and present meaningful data to users. Used by end-user software. Examples: Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), Domain Name System (DNS), Simple Mail Transfer Protocol (SMTP), and Post Office Protocol (POP). Hypertext Transfer Protocol (HTTP): Data protocol used in World Wide Web (Communication between web clients and servers). Communication between client computers and web servers is done by HTTP requests and receiving HTTP responses. Hypertext Transfer protocol Secure (https) is a combination of Hypertext Transfer Protocol (HTTP) with the Secure Socket Layer (SSL)/ Transport Layer Security (TLS) (authentication and security protocol). File Transfer Protocol (FTP): Refers to a group of rules that govern how computers transfer files one system to another over the internet. FTP uses three different modes: block, stream, and compressed. Stream Mode:  It is the d...