Linux commands form the backbone of using and managing a Linux system. This guide covers the most essential commands every Linux user should know.
1. File and Directory Management
List Files and Directories
ls
Options:
ls -l for detailed listing.
ls -a to include hidden files.
Change Directory
cd
Use cd .. to move up one level.
Print Current Directory
pwd
Create a Directory
mkdir
Remove a Directory
rmdir
Use rm -r <directory_name> for non-empty directories.
Copy Files or Directories
cp
Use cp -r for directories.
Move or Rename Files
mv
Delete Files
rm
2. File Viewing and Editing
View File Content
cat
Use tac <file_name> to display content in reverse.
Display File Content Page-by-Page
less
Display First or Last Lines of a File
head
tail
Edit Files
nano
Use vi <file_name> or vim <file_name> for advanced editing.
3. File Permissions and Ownership
View File Permissions
ls -l
Change Permissions
chmod
Examples:
chmod 755 <file_name>
chmod +x <file_name> to make a file executable.
Change Ownership
chown :
4. Process Management
View Running Processes
ps aux
Use top or htop for an interactive process viewer.
Kill a Process
kill
Use kill -9 <process_id> for a forced termination.
Check System Resource Usage
free -h for memory usage.
df -h for disk usage.
5. Networking Commands
Check Network Interfaces and IP Address
ip a
Use ifconfig if ip is unavailable.
Test Network Connectivity
ping
Download Files from the Internet
wget
curl -O
6. Search and Find Commands
Search for Files
find -name
Search Inside Files
grep
Use grep -r <pattern> <directory> for recursive searches.
7. User Management
Add a New User
sudo adduser
Switch Users
su
Check Current User
whoami
8. System Monitoring
Display System Uptime
uptime
View System Logs
journalctl
Use dmesg for kernel logs.
Check Disk Space Usage
df -h
Check Inode Usage
df -i
9. Archiving and Compression
Create a Tar Archive
tar -cvf .tar
Extract a Tar Archive
tar -xvf .tar
Compress Files with Gzip
gzip
Decompress Gzip Files
gunzip .gz
10. Package Management
Debian/Ubuntu-Based Systems
sudo apt-get update
sudo apt-get install
Red Hat/CentOS-Based Systems
sudo yum update
sudo yum install
Arch-Based Systems
sudo pacman -Syu
sudo pacman -S
Learning these commands will help you become proficient in navigating and managing a Linux system.
Use the man command (e.g., man ls) for detailed information about any command.
