🧰 Complete Linux/Unix Commands List & Basic Utilities – Cheat Sheet for Beginners

🧲 Introduction – Why Master Linux/Unix Commands?

At the heart of Linux/Unix is the command line. Whether you’re managing servers, automating scripts, or navigating the file system, knowing the right commands makes you faster and more powerful. These basic utilities are the essential building blocks of everything from system administration to development.

🎯 In this guide, you’ll learn:

• Frequently used Linux/Unix commands and their syntax
• Basic file, directory, and system management tools
• Real examples with practical output
• Categories of commands: navigation, file handling, text processing, system info

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📂 File and Directory Management Commands

Command	Description
pwd	Print current working directory
ls	List files and directories
cd	Change directory
mkdir	Create new directory
rmdir	Remove empty directory
touch	Create a new empty file
rm	Delete files or directories
cp	Copy files or directories
mv	Move or rename files

🧪 Example:

mkdir test
cd test
touch file.txt
ls -l

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📄 File Viewing and Content Commands

Command	Description
cat	View file content
more	View file page-by-page
less	Scrollable file viewer
head	Show beginning of a file
tail	Show last lines of a file
wc	Word, line, and character count
nl	Number lines while displaying content

🧪 Example:

cat myfile.txt
head -n 5 myfile.txt
wc myfile.txt

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✂️ Text Processing Utilities

Command	Description
grep	Search for patterns in text
cut	Remove selected columns/fields
awk	Pattern scanning and processing
sed	Stream editing (find/replace)
sort	Sort lines of text files
uniq	Filter duplicate lines
tr	Translate or delete characters
diff	Compare two files
cmp	Compare files byte by byte

🧪 Example:

grep "error" logs.txt
awk '{print $1}' data.csv
sort names.txt | uniq

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🖥️ System Information Commands

Command	Description
date	Show current date and time
cal	Display calendar
uptime	Show how long system has been running
whoami	Show current user
id	Show UID, GID, and groups
hostname	Show system hostname
uname -a	Display system information
df -h	Disk space usage
free -m	Show memory usage in MB

🧪 Example:

date
uname -a
df -h

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🔄 File Permissions and Ownership

Command	Description
chmod	Change file permissions
chown	Change file ownership
chgrp	Change group ownership
umask	Set default permission mask
stat	Show file metadata

🧪 Example:

chmod 755 script.sh
chown user:group script.sh

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🔧 Process and Job Control

Command	Description
ps	List current processes
top	Real-time process viewer
kill	Send signal to process
jobs	Show background jobs
bg/fg	Resume background/foreground jobs
nice	Set process priority
killall	Kill all processes by name

🧪 Example:

ps aux
kill 1234
top

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📦 Archive and Compression Utilities

Command	Description
tar	Archive files
gzip	Compress files
gunzip	Decompress .gz files
zip	Create ZIP files
unzip	Extract ZIP files

🧪 Example:

tar -czf archive.tar.gz myfolder/
unzip myfile.zip

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🌐 Network Utilities

Command	Description
ping	Check network connectivity
ifconfig	View network interfaces (deprecated for ip)
ip addr	Show IP addresses
netstat	View network connections
ss	Replacement for netstat
curl	Transfer data from/to a server
wget	Download files from the internet
host / dig	DNS lookup

🧪 Example:

ping google.com
curl ifconfig.me
ip addr

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🔎 Search Commands

Command	Description
find	Search for files and directories
locate	Find files quickly using a database
which	Show path of a command
type	Show if a command is built-in or external
whereis	Locate source, binary, and man page of command

🧪 Example:

find /etc -name "*.conf"
which bash

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🛠️ Miscellaneous Utilities

Command	Description
echo	Print text to terminal
history	Show command history
alias	Create shortcut commands
clear	Clear the terminal screen
man	Manual pages for commands
help	Show help for built-in commands

🧪 Example:

alias ll='ls -alF'
history | grep ssh
man tar

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📌 Summary – Recap & Next Steps

🔍 Key Takeaways:

• Linux/Unix provides a wide range of command-line utilities for working with files, processes, networks, and text.
• Each command has options (-l, -h, --help) to customize behavior.
• You can combine commands using pipes (|) and redirection (>, <, >>) for powerful workflows.

⚙️ Mastering these utilities is your gateway to automation, scripting, and professional system administration.

Next: Explore Linux Built-in Functions & System Calls like printf(), fork(), and open().

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❓ FAQs

❓ How can I learn all Linux commands?
✅ Start with frequently used commands (ls, cd, grep) and use man <command> to explore more.

❓ What is the difference between cat, less, and more?
✅ cat prints full content; less and more let you scroll page-by-page. less is more advanced and preferred.

❓ How do I find the path of a command in Linux?
✅ Use which <command> or type <command>.

❓ How can I count the number of lines in a file?
✅ Use:

wc -l filename.txt

❓ How do I search text inside files?
✅ Use:

grep "pattern" filename.txt

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