(TWN) DevOps Prerequisite: Linux
Understanding Linux OS, its file systems and commands is a first important step for anyone who wants to be a DevOps engineer/Cloud Engineer or a IT Infrastructure Engineer.
In this post, we will explore on:
What is Linux? Why is Linux needed? What is it used for? What is the Linux file system? Why is knowing Linux commands important? Commands of Linux.
What is Linux?
Linux is an open-source operating system based on the Unix architecture. It is known for its stability, security, and flexibility, making it a popular choice for servers, desktops, and embedded systems.
Linux distributions, such as Ubuntu, Fedora, and Debian, package the kernel with various software tools and libraries, providing users with a complete operating environment. Linux is widely used in server environments due to its efficiency and reliability.
What is Linux file system?
The Linux file system is a hierarchical structure used to organise and store files on Linux operating systems. The Linux file system is structured in a tree-like format, starting from a root directory denoted by /. All files and directories stem from this root. Note: This is different from windows which uses a drive-letter-based structure where each drive can have its own root.
Why is it important to learn learn? Especially for DevOps engineers
Learning Linux is one of the most valuable IT skills today. Linux powers most of the servers, cloud platforms, and even everyday devices.
Linux commands are executes in our
- Servers (Web servers, enterprise servers and data centres)
- Cloud Servers (Linux VMs)
"Engineers often SSH into cloud servers and execute commands to configure apps, scale workloads, and secure systems"
Linux comes in handy for DevOps engineers as the role involves a lot of provisioning and maintaining of resources.
Why is knowing Linux commands important?
1. Linux command give you direct control over processes, networking and file systems.
2. Shell scripting such as Bash & zsh is the backbone of automation deployment scripts.
3. On servers, we only have CLI (no GUI)
Linux Commands Cheat sheet:
🔍 Navigation & File Management
pwd → Print working directory
ls → List files in directory
cd <dir> → Change directory
touch <file> → Create empty file
cp <src> <dest> → Copy file/directory
mv <src> <dest> → Move/rename file/directory
rm <file> → Remove file
rm -r <dir> → Remove directory recursively
find <path> -name <file> → Search for files
📂 Viewing & Editing Files
cat <file> → View file contents
less <file> → Scroll through file
head <file> → Show first 10 lines
tail <file> → Show last 10 lines
nano <file> → Edit file in Nano editor
vim <file> → Edit file in Vim editor
👥 User & Permission Management
whoami → Show current user
id → Show user ID and groups
adduser <name> → Add new user
passwd <user> → Change password
chmod <perm> <file> → Change file permissions
chown <user>:<group> <file> → Change file owner
⚙️ Process & System Monitoring
ps → Show running processes
top → Real-time process monitoring
htop → Interactive process viewer (if installed)
kill <pid> → Kill process by ID
df -h → Show disk usage
du -sh <dir> → Show directory size
free -h → Show memory usage
uptime → Show system uptime
🌐 Networking
ping <host> → Test connectivity
curl <url> → Fetch data from URL
wget <url> → Download file from URL
ifconfig or ip addr → Show network interfaces
netstat -tulnp → Show active connections
ssh user@host → Connect to remote server
📦 Package Management
(varies by distro)
Debian/Ubuntu:
apt update → Update package list
apt upgrade → Upgrade packages
apt install <pkg> → Install package
RedHat/CentOS:
yum install <pkg> → Install package
dnf update → Update packages
📑 Archiving & Compression
tar -cvf archive.tar <files> → Create tar archive
tar -xvf archive.tar → Extract tar archive
gzip <file> → Compress file
gunzip <file.gz> → Decompress file
zip archive.zip <files> → Create zip archive
unzip archive.zip → Extract zip archive
