Topics Discussed:
- Overview of DevOps- SDLC
- Waterfall and agile models
- DevOps was born, OS Fundamentals
- Linux Overview
- User and File Management
- Shell and SSH
- Process Management
- Directory structure
- Basic commands
Introduction:
Mostly if you are into devops, you will use Linux a lot.
Operating System is an interface between user and hardware.
We usually run software/applications on an OS. We utilise CPU, memory, and storage for this purpose.
The main difference we can see in Linux is we use commands to do everything like everything we do in windows. So as a beginner start with Linux commands.
Linux Fundamentals
CPU executes the process.
Sometimes when a program is huge, it takes time to complete it.
Processes may have one or more executable programs. We need an OS to run the process.
Linux File System
Linux file system converts to a viewable format of what’s in the harddisk. File system in linux follows a tree format. “/” Is the 1st folder in Linux. Each file has an absolute path.
● To create file – touch
● To create folder mkdir
● To view contents – ls
Linux Process
To view the running process – ps -ef (init process starts when we switch on the system, parent is zero)
Each process has a process id and a parent process.
Linux Process Example
1. Initially the SSH process will be running and listens to the ssh connection when a user creates a new ssh connection.
2. When a connection is established, a new process will initiate for “bash” which manages the user command line.
3. User run a command “sudo su – root” in the command line and a new process is started and manages the user command.
4. And so on….
Linux Shell
We execute commands in linux shells. Many shells are available for you to choose from
● Bash
● CH
● CSH
User Management
In windows/Linux we execute different programs. It’s done by a user. In Linux we can create a new user as in windows.
● To add a new user – adduser .
Root users have all permissions. User Management is flexible and different users can login at a time, it won’t cause any problems.
● To switch to a different user account – su
Usually create a user with minimum permission and when the need arises that particular permission can be added to the user.
