Linux Command Line¶

🧠 Overview¶

This wiki provides a quick reference for essential Linux terminal commands. It covers basic navigation, file system operations, search with grep, system monitoring tools (top, htop, btop), CPU and GPU usage (lscpu, nvidia-smi), device detection (lsusb, xrandr), and network diagnostics. The goal is to offer a simple, accessible guide for day-to-day command line tasks and system checks.

🖥️ Linux Command Line Quick Reference¶

pwd – Print current working directory
ls – List files in the current directory
ls -l – Long listing (permissions, size, etc.)
ls -a – Include hidden files
cd <dir> – Change directory
cd .. – Go up one directory
cd ~ – Go to home directory

🔍 Search with `grep`¶

grep "text" file.txt – Search for "text" in file.txt
grep -r "text" /path/ – Recursively search in a directory
grep -i "text" – Case-insensitive search
grep -n "text" – Show line numbers
Combine with ps, dmesg, journalctl for filtering logs

📂 File System and Disk¶

df -h – Disk space usage (human-readable)
du -sh * – Show size of folders/files in current directory
mount – List mounted filesystems
lsblk – List block devices and partitions
find . -name "*.log" – Find files by name
fdisk -l – Show disk partitions

⚙️ System Status¶

top – Real-time process monitor
htop – Improved top (may need sudo apt install htop)
ps aux – List all running processes
uptime – Show system uptime and load average
free -h – Show memory usage
vmstat – System performance overview
dmesg | less – View kernel/system logs

💻 CPU and GPU Usage¶

lscpu – Show CPU architecture info
nproc – Number of available CPU cores
watch -n 1 "grep 'cpu' /proc/stat" – Live CPU stats

GPU (NVIDIA only):

nvidia-smi – Show GPU usage, temperature, memory, running processes (requires NVIDIA drivers)

🔌 Device Detection¶

lsusb – List USB devices
lspci – List PCI devices (e.g., GPUs, network cards)
xrandr – Show connected monitors and resolutions
inxi -F – Full system summary (install with sudo apt install inxi)

📊 Modern System Monitor: `btop`¶

btop – A colorful, interactive resource monitor for CPU, memory, disk, network, and processes
(Install with sudo apt install btop or snap install btop)
Shortcut-friendly and great for quick diagnostics

🌐 Network¶

ip a or ifconfig – Show IP addresses
ping <host> – Test network connectivity
netstat -tuln – Show open ports
ss -tuln – Modern alternative to netstat
curl ifconfig.me – Show your public IP

📦 Package Management (Debian/Ubuntu)¶

sudo apt update – Refresh package list
sudo apt upgrade – Upgrade packages
sudo apt install <pkg> – Install a package
dpkg -l – List installed packages

✨ Cool Tools¶

tmux – Terminal multiplexer to manage multiple terminal sessions in one window (sudo apt install tmux)
yazi – Fast and friendly Markdown viewer for the terminal (install from source or via package manager)
fzf – Command-line fuzzy finder for quick file and command searching
exa – Modern replacement for ls with colors and Git integration
ripgrep (rg) – Fast recursive search tool, alternative to grep
bat – A cat clone with syntax highlighting and Git integration
lazygit – A simple, fast, and intuitive terminal UI for Git. It helps you visualize your repository, stage changes, resolve conflicts, and manage branches without leaving the terminal.
lazydocker – A terminal UI for Docker and Docker Compose. It allows you to manage containers, images, volumes, and networks interactively from your terminal with ease.
zoxide – a smarter cd command, inspired by z and autojump. It remembers which directories you use most frequently, so you can "jump" to them in just a few keystrokes.