Basic Linux Commands
Below is a clear, exam-oriented explanation of basic Linux commands, exactly suitable for BCA / MCA students, beginners, and server basics.
1. Introduction
Linux commands are used to interact with the operating system through the terminal (shell). These commands help users manage files, directories, processes, users, and the system efficiently.
👉 Linux commands follow this format:
command [options] [arguments]
2. File & Directory Commands
pwd – Present Working Directory
Displays the current directory.
pwd
ls – List Directory Contents
Shows files and folders.
ls
ls -l # detailed list
ls -a # show hidden files
cd – Change Directory
Moves between directories.
cd /home/user
cd ..
cd ~
mkdir – Make Directory
Creates a new directory.
mkdir myfolder
rmdir – Remove Empty Directory
rmdir myfolder
3. File Handling Commands
touch – Create Empty File
touch file.txt
cat – Display File Content
cat file.txt
cp – Copy Files
cp file1.txt file2.txt
mv – Move or Rename Files
mv oldname.txt newname.txt
rm – Remove Files
rm file.txt
rm -r foldername
⚠️ Dangerous with root access.
4. Viewing File Content
more
more file.txt
less
less file.txt
(Scrollable, better than more)
head
head file.txt
tail
tail file.txt
tail -f logfile.log
5. User & System Information Commands
whoami
Shows current user.
whoami
who
Shows logged-in users.
who
uname
Displays system information.
uname -a
date
Shows current date & time.
date
6. File Permission Commands
chmod – Change Permissions
chmod 755 file.sh
chown – Change Ownership
chown user:file file.txt
7. Process Management Commands
ps
Shows running processes.
ps
ps -ef
top
Real-time process monitoring.
top
kill
Terminates a process.
kill PID
8. Disk & Memory Commands
df – Disk Free
df -h
du – Disk Usage
du -sh foldername
free – Memory Usage
free -h
9. Networking Commands
ip a
Shows IP address.
ip a
ping
Checks network connectivity.
ping google.com
10. Package Management (Basic)
Ubuntu / Debian
sudo apt update
sudo apt install package_name
RHEL / CentOS
yum install package_name
11. Shutdown & Reboot Commands
shutdown now
reboot
poweroff
12. Help Command (Very Important)
man – Manual
man ls
13. Summary Table (Exam-Friendly)
| Command | Purpose |
|---|---|
ls | List files |
cd | Change directory |
pwd | Current directory |
cp | Copy files |
mv | Move/rename |
rm | Delete |
chmod | Change permissions |
ps | Process status |
top | Live processes |
shutdown | Power off |
14. Conclusion
Basic Linux commands form the foundation of Linux usage and administration. Mastering these commands is essential for system management, server handling, and exam preparation.