Linux FundamentalsComplete Linux System Administrator Roadmap

Level 1: Linux Fundamentals
Level 2: Linux Installation & Environment
Level 3: Linux File System 📁 
Level 4: File Management & Text Processing 📄
Level 5: User & Group Management 👤 
Level 6: Linux Permissions 🔐
Level 7: Package Management 📦
Level 8: Process Management ⚙️
Level 9: Services & systemd 🚀
Level 10: Disk & Storage Management 💾
Level 11: Linux Networking 🌐
Level 12: SSH & Remote Server Administration 🔑
Level 13: Linux Security
Level 14: System Monitoring
Level 15: Log Management & Troubleshooting
Level 16: Bash Shell Scripting 🤖
Level 17: Task Automation with Cron ⏰
Level 18: Web Server Administration 🌍
Level 19: Database Basics 🗄️
Level 20: Linux on Cloud ☁️
Level 21: Docker for Linux Administrators 🐳
Level 22: Configuration Management ⚡
Level 23: Monitoring Tools 📈
Level 24: Advanced Linux Security 🔒
Level 25: High Availability & Advanced Administration 🏗️
Hands-On Projects

Level 1: Linux Fundamentals

1. Understand Linux Basics

Learn:

What is an Operating System?

Popular distributions to know:

• Ubuntu
• Debian
• Red Hat Enterprise Linux (RHEL)
• Rocky Linux / AlmaLinux
• CentOS Stream

Recommended for practice: Ubuntu and Rocky Linux/RHEL-based systems.

 

Level 2: Linux Installation & Environment

Learn how to:

Install Linux on VirtualBox/VMware

Important commands:

uname -a
hostname
hostnamectl
whoami
pwd
date
uptime
history

 

Level 3: Linux File System

Understand the Linux directory structure:

Focus especially on:

• /etc → Configuration files
• /home → User files
• /var → Logs and variable data
• /tmp → Temporary files
• /usr → Programs and libraries
• /root → Root user's home directory

Commands:

ls
cd
pwd
mkdir
rmdir
touch
cp
mv
rm
find
locate
tree
 

Level 4: File Management & Text Processing

Learn how to create, edit, search, and process files.

Commands:
cat
less
more
head
tail
nano
vim
grep
awk
sed
sort
uniq
cut
wc
diff

Examples:

grep "error" logfile.txt

tail -f /var/log/syslog

find /home -name "*.txt"

Important Goal

You should be able to:

• Search inside files
• Monitor logs
• Find files
• Edit configuration files
• Filter command output

 

Level 5: User & Group Management

Learn:

• Root user
• Normal users
• Groups
• UID and GID
• Home directories
• Password management
• Account expiration
• Sudo access

Commands:

useradd
adduser
usermod
userdel
groupadd
groupdel
passwd
id
groups
sudo

Example:

sudo useradd sandeep

sudo passwd sandeep

sudo usermod -aG sudo sandeep

Learn these files:

/etc/passwd
/etc/shadow
/etc/group
/etc/sudoers

 

Level 6: Linux Permissions

This is one of the most important topics for a Linux System Administrator.

Learn:

• Read (r)
• Write (w)
• Execute (x)
• User ownership
• Group ownership
• Others
• Numeric permissions

Example:

rwx = 7

rw- = 6

r-- = 4

Commands:

chmod
chown
chgrp
umask

Examples:

chmod 755 script.sh

chmod 644 file.txt

 

chown user:user file.txt

Also learn:

• SUID
• SGID
• Sticky Bit
• ACL permissions

Commands:

getfacl

setfacl

 

Level 7: Package Management

Ubuntu / Debian

Learn:

apt update
apt upgrade
apt install nginx
apt remove nginx
apt search nginx

RHEL / Rocky Linux

Learn:

dnf install nginx
dnf remove nginx
dnf update
dnf search nginx

Understand:

• Package repositories
• Dependencies
• .deb packages
• .rpm packages
• Repository configuration

 

Level 8: Process Management

Learn what processes are and how Linux manages them.

Commands:

ps
ps aux
top
htop
pgrep
kill
killall
nice
renice
jobs
bg
fg
nohup

Example:

ps aux | grep nginx

 

kill -9 PID

Understand:

PID

 

Level 9: Services & systemd

Modern Linux systems use systemd for service management.

Learn:

systemctl status nginx
systemctl start nginx
systemctl stop nginx
systemctl restart nginx
systemctl enable nginx
systemctl disable nginx

Also learn:

journalctl

Examples:
journalctl -u nginx
journalctl -f

You should understand how to:

• Start services
• Stop services
• Restart services
• Enable services at boot
• Check service logs

 

Level 10: Disk & Storage Management

Very important for a System Administrator.

Learn:

• HDD and SSD
• Partitions
• File systems
• Mounting
• Persistent storage
• Swap

Commands:

lsblk
fdisk -l
df -h
du -sh
mount
umount
blkid

Learn:

MBR

Example:

sudo mount /dev/sdb1 /mnt/data

Advanced Storage in Linux

Learn:

• LVM
• Physical Volume (PV)
• Volume Group (VG)
• Logical Volume (LV)

 

Important commands:

pvcreate
vgcreate
lvcreate
lvextend
resize2fs

 

Level 11: Linux Networking

This is another must-learn topic.

Learn networking basics:

IP Address

 

Commands:

ip a
ip route
ping
hostname -I
ss
curl
wget
nslookup
dig
traceroute

Example:

ping google.com

curl ifconfig.me

ss -tulpn

 

Level 12: SSH & Remote Server Administration

Learn how to manage remote Linux servers.

Commands:

ssh username@server-ip

scp file.txt username@server-ip:/home/user

rsync

Learn:

• SSH keys
• Public key authentication
• Password authentication
• SSH configuration
• Port changes
• Secure remote access

Important file:

/etc/ssh/sshd_config

 

Level 13: Linux Security

Learn basic server security.

Linux Security Important Topics

• User permissions
• sudo
• SSH security
• Firewall
• SELinux
• AppArmor
• File permissions
• Security updates
• Fail2ban
• Log monitoring

Ubuntu Firewall

ufw status
ufw enable
ufw allow 22
ufw allow 80
ufw allow 443

RHEL Firewall

firewall-cmd --state

firewall-cmd --list-all

Level 14: System Monitoring 

Learn how to monitor:

• CPU
• Memory
• Disk
• Network
• Processes
• Logs

Commands:

top
htop
free -h
vmstat
iostat
df -h
du -sh
uptime

Log files to understand:

/var/log/syslog

/var/log/messages

/var/log/auth.log

/var/log/secure

Level 15: Log Management & Troubleshooting

A Linux System Administrator spends a lot of time troubleshooting.

Learn:

journalctl
dmesg
tail -f
grep

Practice troubleshooting problems such as:

• Website is not opening
• Disk is full
• High CPU usage
• High memory usage
• Service is stopped
• Port is blocked
• DNS is not working
• SSH connection is failing
• Permission denied error

Troubleshooting Method of Linux

1. Identify the problem
        ↓
2. Check logs
        ↓
3. Check service status
        ↓
4. Check network
        ↓
5. Check disk and memory
        ↓
6. Fix the issue
        ↓
7. Test again

 

Level 16: Bash Shell Scripting

This is extremely useful for automation.

Learn:

• Variables
• Input/output
• Conditions
• Loops
• Functions
• Arguments
• Exit codes

Example:

#!/bin/bash
 
echo "Hello Sandeep"
 
DATE=$(date)
 
echo "Today is: $DATE"
Then learn:
if
else
for
while
case
function

Practice Projects of Linux

Create scripts for:

• Backup automation
• Disk monitoring
• CPU monitoring
• User creation
• Log cleanup
• Service monitoring

 

Level 17: Task Automation with Cron

Learn how to schedule tasks.

Command:

crontab -e

Example:

0 2 * * * /home/user/backup.sh

This runs a backup script every day at 2:00 AM.

Learn:

Minute
Hour
Day
Month
Day of Week

 

Level 18: Web Server Administration

Nginx with Linux

Learn:

• Install Nginx
• Virtual Hosts / Server Blocks
• Reverse Proxy
• SSL
• Logs

Commands:

systemctl status nginx

nginx -t

Apache with Linux

Learn:

• Virtual Hosts
• Configuration
• Modules
• Logs
• SSL

 

Level 19: Database Basics

You don't need to become a database expert, but a Linux System Admin should know basic database administration.

Learn basics of:

• MySQL
• PostgreSQL

Practice:

mysql -u root -p

Learn:

• Create database
• Create users
• Backup database
• Restore database
• Manage database services

 

Level 20: Linux on Cloud

Since you are learning AWS, this should be a major part of your practice.

Practice Linux administration on:

• EC2
• AWS Lightsail
• Virtual machines

Learn:

• SSH into EC2
• Security Groups
• Elastic IP
• EBS volumes
• Snapshots
• AMIs
• CloudWatch logs and monitoring
• IAM roles for EC2

 

Level 21: Docker for Linux Administrators

Since you have already started learning Docker, connect your Linux knowledge with containers.

Learn:

Linux
   ↓
Docker
   ↓
Containers
   ↓
Docker Networking
   ↓
Volumes
   ↓
Docker Compose

 

Practice:

docker ps
docker images
docker run
docker exec -it
docker logs
docker volume
docker network

 

Level 22: Configuration Management

After becoming comfortable with Linux, learn:

Ansible

Learn:

• Inventory
• Playbooks
• Variables
• Roles
• SSH automation

Example use:

One Ansible Server
        ↓
Manage 10 Linux Servers
        ↓
Install packages

Create users

Configure services

Restart applications

 

Level 23: Monitoring Tools

After basic Linux monitoring, explore professional tools:

• Prometheus
• Grafana
• Nagios
• Zabbix

Learn to monitor:

• CPU
• RAM
• Disk
• Network
• Application health
• Server uptime

Level 24: Advanced Linux Security

Learn:

SELinux

Important command:

getenforce

 

Level 25: High Availability & Advanced Administration

Advanced topics:

• Load balancing
• DNS servers
• NFS
• Samba
• RAID
• LVM
• Backup and recovery
• Disaster recovery
• Clustering basics

 

Recommended 6-Month Learning Plan

Month	Focus
Month 1	Linux basics, commands, filesystem, file management
Month 2	Users, groups, permissions, package management
Month 3	Processes, services, systemd, storage and LVM
Month 4	Networking, SSH, firewall, security
Month 5	Bash scripting, cron, web servers, databases
Month 6	Monitoring, troubleshooting, AWS Linux, Ansible

 

Hands-On Projects for Linux

Build these projects to become job-ready:

Project 1: User Management Server

Create users, groups, sudo permissions, and password policies.

Project 2: Secure Linux Server

Configure:

SSH
Firewall
Fail2ban
User permissions
Security updates

Project 3: Web Server

Deploy an HTML website using:

Linux Server
   ↓
Nginx
   ↓
Domain
   ↓
SSL Certificate

 

Project 4: Automated Backup System

Create a Bash script that:

• Takes a backup.
• Compresses files.
• Adds the date.
• Deletes old backups.
• Runs automatically using Cron.

Project 5: Disk Monitoring Script

Create a script that checks disk usage and alerts when usage crosses a limit.

Project 6: Multi-Server Management

Use Ansible to:

• Create users
• Install Nginx
• Copy website files
• Start services

across multiple Linux servers.

 

Final Career Roadmap for Linux

Linux Fundamentals
        ↓
Linux Commands & Filesystem
        ↓
Users & Permissions
        ↓
Package Management
        ↓
Processes & Services
        ↓
Storage & LVM
        ↓
Networking & SSH
        ↓
Security & Firewall
        ↓
Logs & Troubleshooting
        ↓
Bash Scripting
        ↓
Cron & Automation
        ↓
Web Servers
        ↓
Cloud (AWS)
        ↓
Docker
        ↓
Ansible
        ↓
Monitoring
        ↓
Linux System Administrator
        ↓
DevOps Engineer / Cloud Engineer

 

My recommendation for Linux beginners

Focus first on these 10 core skills:

1. Linux commands
2. Filesystem
3. Users and groups
4. Permissions
5. Package management
6. Processes and systemd
7. Networking
8. Storage and LVM
9. Bash scripting
10. Troubleshooting

Then move to AWS + Docker + Ansible + Monitoring. This path fits very well with your existing AWS and Docker learning and can eventually take you toward a Linux System Administrator, Cloud Engineer, or DevOps Engineer role.

ompany: Wipro
Role: DevOps Engineer
Experience Required: 5–8 Years
Interview Mode: Virtual
Interview Date: 10-Sep-2026

🔹 LINUX + SHELL SCRIPTING
• 01) How would you troubleshoot high CPU and memory usage on Linux?
• 02) How do you identify the cause of disk I/O bottlenecks?
• 03) Write a Bash approach to monitor and restart a failed service.
• 04) How would you troubleshoot DNS or connectivity issues from Linux?
• 05) How do you safely manage processes, signals and system resources?
• 06) How would you investigate a sudden spike in open file descriptors?
• 07) How do you automate log cleanup without impacting running services?

🔹 DOCKER + CONTAINERS
• 08) How would you optimize a large Docker image?
• 09) Explain multi-stage builds for production containers.
• 10) How do you troubleshoot a container that repeatedly exits?
• 11) How would you securely manage secrets in containers?
• 12) How do Docker networking modes affect service communication?
• 13) How would you reduce container startup time?

🔹 KUBERNETES
• 14) How would you troubleshoot a Pod stuck in CrashLoopBackOff?
• 15) How do you diagnose Pending Pods caused by scheduling constraints?
• 16) How would you troubleshoot a Kubernetes Service returning 503?
• 17) How do readiness and liveness probes affect production availability?
• 18) How would you configure HPA for unpredictable traffic?
• 19) When would you use rolling, blue-green or canary deployments?
• 20) How do you manage application configuration and secrets?
• 21) How would you troubleshoot node-level failures in EKS/AKS/GKE?
• 22) How do Helm charts support reusable Kubernetes deployments?

🔹 CI/CD
• 23) How would you design a secure Jenkins or GitHub Actions pipeline?
• 24) A deployment succeeds but the application fails. How do you debug it?
• 25) How would you implement automated rollback in CI/CD?
• 26) How do you manage artifacts across environments?
• 27) How would you add quality and security gates to a pipeline?
• 28) How do you prevent concurrent deployments from causing conflicts?

🔹 CLOUD + INFRASTRUCTURE
• 29) How would you design highly available infrastructure on AWS/Azure/GCP?
• 30) How do load balancers and auto scaling work together?
• 31) How would you design disaster recovery for a critical service?
• 32) How would you troubleshoot sudden cloud cost increases?
• 33) How would you secure S3/ADLS/GCS data and access?
• 34) How would you design networking between private cloud workloads?

🔹 TERRAFORM + IaC
• 35) How would you structure Terraform for multiple environments?
• 36) How do you handle Terraform state locking and drift?
• 37) How would you safely manage secrets in Terraform?
• 38) How do modules improve large-scale infrastructure management?
• 39) How would you recover from a failed Terraform deployment?