What Is Linux and How It Works

Linux is a free, open-source operating system kernel first written by Linus Torvalds in 1991. It powers everything from smartphones and embedded devices to web servers, supercomputers, and cloud infrastructure. Unlike proprietary operating systems, Linux is developed collaboratively by thousands of contributors worldwide and is distributed under the GNU General Public License. The term "Linux" most commonly refers to a complete operating system distribution (distro) that bundles the Linux kernel with system utilities, package managers, desktop environments, and application software. Popular distributions include Ubuntu, Debian, Fedora, Arch Linux, and CentOS/Rocky Linux, each targeting different use cases from beginner desktops to enterprise servers. At its core, Linux follows the Unix philosophy: small, focused programs that do one thing well and can be composed together. Understanding this design principle helps you unlock the true power of the command line — chaining commands, automating tasks, and managing systems with precision and efficiency.

Example

# Check the kernel version
uname -r
# Example output: 6.5.0-45-generic

# Display full system information
uname -a
# Linux hostname 6.5.0-45-generic #45~22.04.1-Ubuntu SMP ...

# Show the Linux distribution name and version
cat /etc/os-release
# NAME="Ubuntu"
# VERSION="22.04.3 LTS (Jammy Jellyfish)"

# List installed package counts (Debian/Ubuntu)
dpkg -l | wc -l

# Check how long the system has been running
uptime
# 14:23:01 up 5 days, 3:12,  2 users,  load average: 0.08, 0.10, 0.09

# Display memory usage
free -h
#               total   used   free  shared  buff/cache  available
# Mem:           15Gi   3.2Gi  8.1Gi  312Mi   4.0Gi       11Gi

# Show disk usage of all mounted filesystems
df -h

# Display CPU information
lscpu | grep -E 'Model name|CPU\(s\)|Thread'

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