Skip to content

Basic Linux Commands for Begin.md

Latest commit

 

History

History
121 lines (98 loc) · 6.79 KB

Basic Linux Commands for Begin.md

File metadata and controls

121 lines (98 loc) · 6.79 KB

📘 Basic Linux Commands for Beginners (L1 Level)

Welcome to the cybersecurity-note repository — this document provides a beginner-friendly breakdown of essential Linux commands. These commands are foundational for L1-level learners stepping into system administration, cybersecurity labs, or ethical hacking environments.

Each command includes:

  • ✅ Basic definition
  • 💡 Practical example
  • 🎯 When and why to use
  • 🖥️ Real-world usage reference

📂 1. Basic Linux Commands

Command Example Purpose
ls ls Lists directory contents
cd cd /var/log Changes directory
pwd pwd Shows current directory path
mkdir mkdir test_dir Creates a new directory
rmdir rmdir test_dir Deletes an empty directory
touch touch file.txt Creates a new empty file
rm rm file.txt Removes a file
cp cp file.txt /tmp/ Copies a file
mv mv file.txt backup.txt Moves or renames a file
man man ls Opens the manual page for a command
echo echo "Hello World" Prints a message to terminal
chmod chmod 755 script.sh Changes file permissions
chown chown user:user file.txt Changes file ownership
ps ps aux Lists active processes
kill kill 1234 Terminates process by PID
top top Real-time system monitoring
df df -h Shows disk space usage
du du -sh /etc/ Shows directory size
cat cat file.txt Displays file content
nano / vi nano file.txt Edits a file in terminal
clear clear Clears terminal screen
exit exit Logs out from terminal

🌐 2. Networking Commands

Command Example Use Case
ping ping google.com Check connectivity to a remote host
ifconfig / ip a ip a View network interface details
netstat netstat -tuln View active ports and services
traceroute traceroute google.com View route packets take
nslookup nslookup example.com DNS lookup for domain/IP mapping
dig dig example.com Advanced DNS queries
route route -n View routing table
ss ss -tuln Analyze network socket connections
iwconfig iwconfig Wireless interface settings

⚙️ 3. Service Management

Command Example Purpose
systemctl systemctl status ssh Manage systemd services
service service apache2 start Init-based service control
journalctl journalctl -u ssh View service logs
chkconfig chkconfig --list Manage SysV services
ufw ufw allow 22/tcp Firewall rule management

🧑‍💻 4. System Administration

Command Example Usage
sudo sudo apt update Run command as superuser
apt-get/yum/dnf sudo apt install nmap Install packages
passwd passwd Change user password
useradd/userdel useradd testuser Manage user accounts
groupadd/groupdel groupadd devs Manage groups
free free -m Show system memory
uname uname -a System information
lshw lshw -short Hardware summary
shutdown/reboot shutdown -h now Power off or reboot
crontab crontab -l View scheduled tasks
tar tar -czvf archive.tar.gz folder/ Archive files
gzip/gunzip gzip file.txt Compress/decompress

🗂️ 5. Linux Directory Structure Explained

Directory Description
/ Root directory of the Linux filesystem
/bin Essential user binaries (e.g., ls, cat)
/etc Configuration files
/home User home directories
/var Log files, databases, spool directories
/usr Secondary hierarchy (apps/libraries)
/lib Essential shared libraries
/dev Device files
/tmp Temporary files
/opt Optional/additional software packages
/sbin System binaries for root user
/srv Site-specific service data
/proc Kernel and process information (virtual FS)
/sys Interface to kernel subsystems
/run Runtime process data
/boot Bootloader and kernel files
/mnt Temporary mount point
/media Mount point for external devices

🔐 License

This repository is licensed under the MIT License. Use responsibly.

Maintained by: @hackwithvyshu | Contact: Vaishnavcv978@gmail.com