DevOps Journey: PART ONE

Continuing my 90-day DevOps journey with the TrainWithShubhm platform, I have progressed to phase one, where I learned to access AWS cloud instances using Ubuntu and grasped basic Linux commands. Under the guidance of Shubham Sir, I delved into the foundational aspects of Linux, which are crucial for DevOps practices. This blog will provide a detailed overview of what I learned, elaborating on each command and its application.

Accessing AWS Cloud Instances

To begin with, I learned how to access AWS cloud instances. AWS (Amazon Web Services) provides scalable and reliable cloud computing services. Using AWS, we can deploy virtual servers (instances) running various operating systems, including Ubuntu Linux.

Basic Linux Commands

System Information and Basic Commands

lsb-release: Displays Linux distribution information.
```
 bashCopy codelsb_release -a
```
date: Displays or sets the system date and time.
```
 bashCopy codedate
```
echo: Prints text to the terminal.
```
 bashCopy codeecho "Hello, World!"
```
mkdir: Creates a new directory.
```
 bashCopy codemkdir new_directory
```
touch: Creates an empty file or updates the timestamp of an existing file.
```
 bashCopy codetouch new_file.txt
```
pwd: Prints the current working directory.
```
 bashCopy codepwd
```
cd: Changes the current directory.
```
 bashCopy codecd /path/to/directory
```

File and Directory Management

df -h: Displays disk space usage in a human-readable format.
```
 bashCopy codedf -h
```

cp: Copies files or directories.

 bashCopy codecp source_file.txt destination_file.txt

rm -r: Removes files or directories recursively.
```
bashCopy coderm -r directory_name
```

mv: Moves or renames files or directories.

bashCopy codemv old_name.txt new_name.txt

cd /: Changes to the root directory.
```
bashCopy codecd /
```
cd dev: Changes to the /dev directory, which contains device files.
```
bashCopy codecd /dev
```
cd bin: Changes to the /bin directory, which contains essential binary executables.
```
bashCopy codecd /bin
```
cd var: Changes to the /var directory, which contains variable data files.
```
bashCopy codecd /var
```

Network Commands

ping: Checks the connectivity to another network host.
```
bashCopy codeping google.com
```

User and Group Management

sudo: Executes commands with superuser privileges.
```
bashCopy codesudo command
```
whoami: Displays the current logged-in user.
```
bashCopy codewhoami
```
adduser: Adds a new user.
```
bashCopy codesudo adduser new_username
```
groupadd: Creates a new group.
```
bashCopy codesudo groupadd new_group
```

usermod -aG: Adds a user to a group.

bashCopy codesudo usermod -aG group_name username

passwd: Changes the user password.
```
bashCopy codesudo passwd username
```

File Permissions

chmod: Changes the file permissions.
```
bashCopy codechmod 755 filename
```

Package Management

apt-get install: Installs packages using the APT package manager.
```
bashCopy codesudo apt-get install package_name
```
apt-update: Updates the package lists.
```
bashCopy codesudo apt-get update
```

Text Editors

vim: Opens the Vim text editor.
```
bashCopy codevim filename
```

File Viewing and Searching

cat: Concatenates and displays file content.
```
bashCopy codecat filename
```
head: Displays the first few lines of a file.
```
bashCopy codehead filename
```
tail: Displays the last few lines of a file.
```
bashCopy codetail filename
```

grep: Searches for patterns within files.

bashCopy codegrep "search_pattern" filename

cat /etc/passwd: Displays the contents of the passwd file, which contains user account information.
```
bashCopy codecat /etc/passwd
```

Creating and Managing Users and Groups

Creating New Users

To create a new user, use the adduser command followed by the username:

bashCopy codesudo adduser new_username

This command will prompt you to set a password and fill in user details.

Creating New Groups

To create a new group, use the groupadd command followed by the group name:

bashCopy codesudo groupadd new_group

Adding Users to Groups

To add a user to a group, use the usermod command with the -aG option:

bashCopy codesudo usermod -aG group_name username

Changing User Passwords

To change a user's password, use the passwd command followed by the username:

bashCopy codesudo passwd username

Changing File Permissions

To change file permissions, use the chmod command:

Understanding File Permissions

In Linux, file permissions are represented by a set of 10 characters, for example: -rwxr-xr-x.

The first character represents the file type (- for regular file, d for directory).
The next nine characters represent the permissions, divided into three sets of three characters each:
- Owner permissions: The first three characters (rwx) specify read (r), write (w), and execute (x) permissions for the file's owner.
- Group permissions: The middle three characters (r-x) specify read and execute permissions for the group members.
- Others permissions: The last three characters (r-x) specify read and execute permissions for all other users.

Here's a table summarizing common permission settings:

---	0	No permissions
--x	1	Execute
-w-	2	Write
-wx	3	Write and execute
r--	4	Read
r-x	5	Read and execute
rw-	6	Read and write
rwx	7	Read, write, execute

Binary	Numeric	Description
000 000 000	000	No permissions
000 000 001	001	Execute only for others
000 000 010	002	Write only for others
000 000 011	003	Write and execute for others
000 000 100	004	Read only for others
000 000 101	005	Read and execute for others
000 000 110	006	Read and write for others
000 000 111	007	Read, write, and execute for others
111 111 111	777	Read, write, and execute for all
110 110 110	666	Read and write for all

bashCopy codechmod 755 filename

This command sets the permissions to read, write, and execute for the owner, and read and execute for the group and others.

Conclusion

Today's session provided me with essential skills to navigate and manage a Linux environment, a critical component in DevOps. I learned to access AWS cloud instances, execute basic Linux commands, and manage users and groups. These skills lay a strong foundation for more advanced DevOps practices.

A big thank you to the TrainWithShubhm platform and Shubham Sir for guiding me through this journey. Stay tuned as I continue to dive deeper into the world of DevOps with the TrainWithShubhm platform. Each day promises new insights and skills that will pave the way for a successful career in DevOps.

#TrainWithShubhm #ShubhamSir #90DaysOfDevOps