Master Linux Basics: From Shell Commands to System Management

Introduction

Linux is a crucial skill for programmers, especially for front‑end developers who have fewer opportunities to work with it compared to back‑end developers.

Linux Fundamentals

Operating System

An operating system (OS) is the software layer that manages hardware resources and provides basic services to applications.

What Is Linux?

Linux refers to the kernel, while a Linux distribution (distro) combines the kernel with a collection of software packages.

Linux vs Windows

Stable and efficient

Free or low‑cost

Fewer vulnerabilities and quick patches

Multi‑user and multitasking

Strong security model

Suitable for embedded systems

Low resource consumption

Popular Distributions

RHEL (Red Hat Enterprise Linux)

Fedora

CentOS

Deepin

Debian

Ubuntu

Connecting to a Server

Use SSH to log in to a remote Alibaba Cloud ECS instance:

ssh [email protected]

Shell Overview

The shell provides a command‑line interface (CLI) for interacting with the OS. Common shells include Bash, Zsh, Fish, etc.

Common Shell Commands

pwd

– display current directory ls – list files (options: -a, -l, -h, -t, -i) cd – change directory du – show directory size cat, less, head, tail – view file contents cp, mv, rm – copy, move, delete files mkdir, rmdir – create, remove directories

File and Directory Management

Use chmod, chown, and chgrp to control permissions and ownership.

# Example: give user read/write/execute
chmod 740 file.txt

User and Group Management

Create users with useradd, set passwords with passwd, and manage groups with groupadd, usermod, etc.

Searching Files

Use locate for quick name searches and find for powerful criteria (name, size, time).

find / -name "*.log" -size +10M

Software Repositories and Package Management

Linux packages are stored in repositories. Manage them with yum (CentOS/RHEL) or apt (Debian/Ubuntu).

yum install vim
yum update
yum remove httpd

Manual Pages

Use man to read command documentation, or command --help for a quick summary.

Advanced Topics

Redirection and Pipes

Redirect output with > (overwrite) or >> (append). Combine commands with a pipe |.

ls -l | grep "\.conf"

Process Management

View processes with ps, top, or w. Control them with kill, bg, fg, jobs, and nohup.

Daemons and systemd

System services run as daemons (PID 1). Manage them with systemctl (start, stop, enable, status).

systemctl start nginx
systemctl enable nginx

Compression and Archiving

Create archives with tar and compress with gzip or bzip2. Extract with tar -xvf.

tar -czvf archive.tar.gz /path/to/dir

Compiling Software from Source

Typical steps: download source, tar -xvf, ./configure, make, make install.

Networking Basics

Check IP configuration with ifconfig (or ip addr). Resolve hostnames with host. Transfer files with scp or rsync.

Vim Editor

Vim has three main modes: Normal (navigation), Insert (editing), and Command (ex commands). Common actions:

Enter Insert mode: i, a, o Delete: x, dd, dw Copy/Yank: yy, yw Paste: p Search: /pattern and n / N Replace: :%s/old/new/g Configure Vim permanently in ~/.vimrc (e.g., set number, syntax on).

Conclusion

By mastering these Linux commands, concepts, and tools, programmers can efficiently manage systems, automate tasks, and develop robust applications across diverse environments.