Linux vs Windows and macOS: Key Differences

Posted on Feb 18, 2026 in Computers

⚖️ Comparison of Linux with Other Operating Systems

Linux, along with Microsoft Windows and Apple macOS, forms the triad of major operating systems. For exam purposes, the comparison focuses on their fundamental differences in cost, source model, security, and primary use case.

Fundamental Distinctions (Source Model & Cost)

Feature	Linux (e.g., Ubuntu, Fedora)	Microsoft Windows (Proprietary)	Apple macOS (Proprietary)
Source Model	Open source (source code is freely available, modifiable, and distributable).	Closed source (proprietary; source code is hidden).	Closed source (proprietary; based on a BSD UNIX core).
Cost	Free to obtain and use.	Requires a paid license.	Included with Apple hardware (which is typically costly).
Licensing	Governed by licenses like the GPL (General Public License), granting four freedoms.	Governed by an EULA (End-User License Agreement), restricting usage and modification.	Governed by an EULA.
Hardware	Most flexible; runs on many architectures (x86, ARM, etc.), often reviving old hardware.	Runs on a vast range of PC hardware.	Least flexible; typically runs exclusively on Apple hardware.

Technical and Use-Case Comparison

Feature	Linux	Windows	macOS
Security	Highest. Robust UNIX-like permissions, rapid community-driven patch cycles, and a less common target for mainstream malware.	Moderate. Most frequent target for malware due to a massive user base.	High. Strong security based on its UNIX foundation.
Stability	Highest. Known for continuous uptime (years) in server environments.	High in modern versions, but historically prone to issues.	High; known for reliability and a polished user experience.
File System	Case-sensitive (e.g., `File.txt` ≠ `file.txt`).	Case-insensitive (e.g., `File.txt` = `file.txt`).	Case-insensitive by default, but supports case-sensitive volumes.
Primary Shell	Bash (most common), Zsh, Fish — powerful and scriptable.	PowerShell / Command Prompt (or Bash via WSL).	Zsh (modern default) / Bash — powerful, UNIX-like.
Primary Use	Servers, cloud computing, embedded systems, software development, academic research.	General desktop, gaming, corporate/business productivity.	Creative professionals (video/audio/design), consumer desktop.

Conclusion for Exam Purposes

In an examination, when comparing Linux to its proprietary counterparts, the core points to emphasize are:

Open Source vs. Proprietary: Linux’s transparency and freedom of modification (GPL).
Stability and Security: Linux’s multi-user/multitasking design and stringent permission model make it fundamentally more robust for mission-critical tasks (servers).
Command Line Power: The highly efficient and essential command-line interface (CLI), typically Bash, provides a level of control and automation superior for professional IT and development work.

💻 Essential Linux Commands

This list categorizes key Linux commands crucial for system administration and development, focusing on their function and common usage.

1. General-Purpose Commands

These commands handle basic system interaction, documentation, and information retrieval.

Command	Function	Key Option/Usage
`man`	Displays the manual page (documentation) for any command or system component.	`man ls`
`info`	Provides more detailed, structured documentation than `man`.	`info bash`
`date`	Displays or sets the system time and date.	`date`
`who`	Shows who is currently logged in to the system.	`who`
`clear`	Clears the terminal screen.	`clear`
`echo`	Prints text or variables to the standard output.	`echo $PATH`

2. Directory-Oriented Commands (Navigation & Structure)

These commands manage the hierarchical file-system structure.

Command	Function	Key Option/Usage
`pwd`	Prints working directory (shows current location).	`pwd`
`cd`	Changes directory.	`cd /home/user` or `cd ..` (up one level)
`ls`	Lists directory contents.	`ls -l` (long format) or `ls -a` (all files, including hidden)
`mkdir`	Makes a new directory.	`mkdir new_folder`
`rmdir`	Removes an empty directory.	`rmdir empty_folder`
`tree`	Displays directory contents in a tree-like format (if installed).	`tree /etc`

3. File-Oriented Commands (Manipulation & Content)

These commands handle file creation, copying, moving, deleting, and content viewing.

Command	Function	Key Option/Usage
`touch`	Creates an empty file or updates file timestamps.	`touch newfile.txt`
`cat`	Concatenates and prints file contents to the terminal.	`cat file.txt`
`less`	Views large files one screen at a time (allows scrolling).	`less logfile.log`
`cp`	Copies files and directories.	`cp source.txt dest/`
`mv`	Moves (renames) files and directories.	`mv oldname.txt newname.txt`
`rm`	Removes (deletes) files.	`rm file.txt` or `rm -rf directory` (force recursive delete)
`grep`	Searches for a pattern within file contents.	`grep "keyword" file.txt`
`find`	Searches for files and directories based on various criteria.	`find /home -name "*.log"`

4. Process-Oriented Commands

These commands manage and monitor running programs (processes).

Command	Function	Key Option/Usage
`ps`	Reports a snapshot of the currently running processes.	`ps aux` (shows all processes)
`top`	Displays processes dynamically in real time (CPU/Memory usage).	`top`
`htop`	An interactive, improved version of `top` (if installed).	`htop`
`kill`	Sends a signal (e.g., termination) to a process using its PID (Process ID).	`kill 1234` (default is signal 15, graceful termination)
`killall`	Sends a signal to all processes with a specific name.	`killall firefox`
`&`	Executes a command in the background.	`sleep 60 &`

5. Communication-Oriented Commands

These commands facilitate user-to-user communication or network interaction.

Command	Function	Key Option/Usage
`ssh`	Secure Shell: securely logs into a remote system.	`ssh user@server_ip`
`scp`	Secure Copy: securely transfers files between hosts.	`scp localfile.txt user@server:/tmp`
`ping`	Tests network connectivity and measures packet round-trip time.	`ping google.com`
`wget`	Non-interactively retrieves files from the web (downloading).	`wget <URL>`
`write`	Sends a message to another user’s terminal session.	`write username`
`wall`	Write to all logged-in users’ terminals (administrator announcements).	`wall "System maintenance in 1 hour"`

🔎 Regular Expressions & Filters in Linux

Filters and regular expressions (regex) are fundamental tools in Linux for processing text data, especially when dealing with command output, logs, and configuration files.

🔧 Simple Linux Filters

In Linux, a filter is a program that reads data from standard input (stdin), processes it, and writes the resulting data to standard output (stdout). Filters are often used in combination with the pipe operator (|).

Command	Function	Key Option/Usage	Example
`more`	Used to display text output one screenful at a time.	`ls -l \| more`
`wc`	Word count: prints the number of lines, words, and bytes (characters) in a file.	`wc -l file.txt`	Counts only the lines in `file.txt`.
`diff`	Finds the differences between two files, line by line.	`diff file1.txt file2.txt`	Shows which lines differ and how to change them.
`sort`	Sorts the lines of text files.	`sort -r data.txt`	Sorts the lines in `data.txt` in reverse alphabetical order.
`uniq`	Reports or omits repeated lines. It only works on adjacent identical lines, so it is often used after `sort`.	`sort names.txt \| uniq`
`grep`	Global Regular Expression Print: searches for lines matching a specified pattern (regular expression).	`grep -i "error" logfile.log`	Searches for “error” case-insensitively in the log file.

📜 Introducing Regular Expressions (Regex)

Regular expressions are specialized text strings used to describe and match patterns in other strings or text files. They are essential for advanced searching and data manipulation, especially with tools like grep, sed, and awk.

Basic Regex Components

Regex uses special characters, called metacharacters, to define patterns:

Metacharacter	Description	Example Pattern	Matches
`.` (dot)	Matches any single character (except a newline).	`a.c`	`abc`, `a1c`, `a-c`
`*`	Matches the preceding item zero or more times.	`a*b`	`b`, `ab`, `aaab`
`+`	Matches the preceding item one or more times (used with egrep/PCRE).	`a+b`	`ab`, `aaab` (but not `b`)
`?`	Matches the preceding item zero or one time (used with egrep/PCRE).	`colou?r`	`color`, `colour`
`^`	Matches the pattern at the beginning of a line.	`^Start`	Matches “Start line” but not “The Start line”
`$`	Matches the pattern at the end of a line.	`End$`	Matches “Line End” but not “End of line”
`[ ]`	Character set: matches any one of the characters inside the brackets.	`[abc]`	Matches `a`, `b`, or `c`
`[^ ]`	Negated character set: matches any character not inside the brackets.	`[^0-9]`	Matches any non-digit character.

Regex Tools in Linux

The grep utility supports three main types of regular expressions:

Basic Regular Expressions (BRE): The default for the standard grep command. It requires metacharacters like +, ?, |, and {} to be escaped with a backslash (\).
Example: grep "a\{2,\}b" file matches ‘a’ appearing 2 or more times followed by ‘b’.
Extended Regular Expressions (ERE): Enabled using the egrep command or the grep -E option. This syntax simplifies usage by allowing metacharacters like +, ?, and | to be used without escaping.
Example: egrep "a+b" file matches ‘a’ appearing 1 or more times followed by ‘b’.
Perl Compatible Regular Expressions (PCRE): Enabled using grep -P. This provides the most modern and powerful set of regex features.

🧠 Example Usage

To find all lines in a file that start with an uppercase letter followed by any number of lowercase letters:

grep -E "^[A-Z][a-z]*" mydata.txt

grep -E: uses extended regular expressions.
^: matches the beginning of the line.
[A-Z]: matches one uppercase letter.
[a-z]*: matches zero or more lowercase letters.