🐧 Daily Linux Commands

📂 File and Directory Commands

• man — Skim through manual for better understanding
• vi — Available by default and Lightweight editor, but has a steep learning curve. Not a beginner friendly.
• nano — Often available, Simple and intuitive, great for quick edits.
• vim — Not a pre-installed, "Vi Improved" — powerful, customizable, widely used by developers
• ls -l — List files with permissions and sizes, detailed info
• cd /path/to/dir — Change directory
• mkdir folder — Create a new folder
• rm -rf folder — Delete a folder and contents recursively Destructive command
• cp file1 file2 — Copy file1 to file2
• mv old new — Rename or move a file

🔍 Searching & Filtering

• grep 'text' file — Search for text in a file
• find . -name "*.sh" — Find all shell scripts recursively
• grep -r 'pattern' ./ — Recursive grep from current directory

📊 Disk and System Info

• df -h — Show disk usage in human-readable format
• du -sh * — Show folder sizes in current directory
• free -m — Show memory usage in MB
• top — Real-time process monitor
• uname -a — Show kernel and system info

🛠️ Permissions & Ownership

• chmod +x script.sh — Make a script executable
• chown user:group file — Change file owner
• chmod 755 file — Set permissions (rwxr-xr-x)

📦 Package Management

🟢 Debian / Ubuntu (APT)

• sudo apt update — Refresh package database
• sudo apt upgrade — Install available updates
• sudo apt install packagename — Install a package
• dpkg -l — List all installed packages
• sudo dpkg -i file.deb — Install a downloaded .deb package

🔴 RHEL / CentOS / Fedora (RPM/YUM)

• sudo yum update — Update all installed packages (RHEL 7 and below)
• sudo dnf update — For newer systems (RHEL 8+ / Fedora)
• sudo yum install packagename — Install a package
• sudo rpm -ivh file.rpm — Install a local .rpm file
• rpm -qa — List all installed RPM packages
• rpm -ql packagename — Show installed files of a package

⚙️ Process Management

• ps aux — List all running processes
• kill -9 PID — Force kill a process by PID
• htop — Interactive process viewer (if installed)