Terminal.txt

# TERMINAL - Command Line Interface Reference - by Richard Rembert

# The command line is a powerful tool for developers to interact with their computer
# This reference covers essential commands for Unix-like systems (macOS, Linux) and Windows

# GETTING STARTED

# Open Terminal/Command Prompt:
# macOS: Cmd + Space, type "Terminal"
# Windows: Win + R, type "cmd" or "powershell"
# Linux: Ctrl + Alt + T (most distributions)

# Basic command structure:
# command [options] [arguments]
# Example: ls -la /home/user


# NAVIGATION COMMANDS

# Print working directory (current location)
pwd

# List directory contents
ls                    # Basic list
ls -l                 # Long format (detailed)
ls -la                # Long format including hidden files
ls -lh                # Human readable file sizes
ls -R                 # Recursive (show subdirectories)
ls *.txt              # List only .txt files
ls -t                 # Sort by modification time
ls -S                 # Sort by file size

# Windows equivalent
dir                   # Basic directory listing
dir /a                # Show all files including hidden
dir /s                # Recursive listing

# Change directory
cd /path/to/directory # Absolute path
cd ../                # Go up one directory
cd ~                  # Go to home directory
cd -                  # Go to previous directory
cd                    # Go to home directory (no arguments)

# Create directory
mkdir new_folder              # Create single directory
mkdir -p path/to/new/folder   # Create nested directories
mkdir folder1 folder2 folder3 # Create multiple directories

# Remove directory
rmdir empty_folder            # Remove empty directory
rm -r folder                  # Remove directory and contents (recursive)
rm -rf folder                 # Force remove without prompts


# FILE OPERATIONS

# Create empty file
touch filename.txt            # Unix/Linux/macOS
echo. > filename.txt          # Windows

# Copy files
cp source.txt destination.txt        # Copy file
cp -r source_folder dest_folder      # Copy directory recursively
cp *.txt backup/                     # Copy all .txt files to backup folder
cp file.txt{,.backup}               # Quick backup (creates file.txt.backup)

# Windows copy
copy source.txt destination.txt      # Copy file
xcopy source dest /E /I              # Copy directory

# Move/rename files
mv old_name.txt new_name.txt         # Rename file
mv file.txt /path/to/destination/    # Move file
mv *.txt documents/                  # Move all .txt files

# Windows move
move old_name.txt new_name.txt       # Rename file
move file.txt C:\destination\        # Move file

# Remove files
rm filename.txt              # Remove file
rm *.txt                     # Remove all .txt files
rm -i filename.txt           # Interactive removal (asks for confirmation)
rm -f filename.txt           # Force removal without prompts

# Windows delete
del filename.txt             # Delete file
del *.txt                    # Delete all .txt files


# FILE VIEWING AND EDITING

# View file contents
cat filename.txt             # Display entire file
less filename.txt            # View file page by page (q to quit)
more filename.txt            # Similar to less
head filename.txt            # Show first 10 lines
head -n 20 filename.txt      # Show first 20 lines
tail filename.txt            # Show last 10 lines
tail -f filename.txt         # Follow file (useful for logs)

# Windows file viewing
type filename.txt            # Display entire file
more filename.txt            # View file page by page

# Edit files
nano filename.txt            # Simple text editor (Ctrl+X to exit)
vi filename.txt              # Vi editor (press i to insert, :wq to save and quit)
vim filename.txt             # Vim editor (enhanced vi)
code filename.txt            # Open in VS Code (if installed)

# Windows edit
notepad filename.txt         # Open in Notepad


# SEARCH AND FIND

# Find files
find . -name "*.txt"                    # Find all .txt files in current directory
find /home -name "config*"              # Find files starting with "config"
find . -type d -name "node_modules"     # Find directories named "node_modules"
find . -size +100M                      # Find files larger than 100MB
find . -mtime -7                        # Find files modified in last 7 days

# Locate files (faster, uses database)
locate filename.txt                     # Find file by name
updatedb                                # Update locate database (run as sudo)

# Windows find
dir /s filename.txt                     # Search for file recursively
where filename.exe                      # Find executable in PATH

# Search inside files
grep "search_term" filename.txt         # Search for text in file
grep -r "search_term" .                 # Search recursively in all files
grep -i "search_term" filename.txt      # Case-insensitive search
grep -n "search_term" filename.txt      # Show line numbers
grep -v "search_term" filename.txt      # Show lines that DON'T contain term
grep -E "pattern1|pattern2" file.txt    # Search for multiple patterns

# Windows search
findstr "search_term" filename.txt      # Search for text in file
findstr /s "search_term" *              # Search in all files


# FILE PERMISSIONS (Unix/Linux/macOS)

# View permissions
ls -l filename.txt           # Shows permissions like -rw-r--r--

# Permission format: type|owner|group|others
# - = file, d = directory
# r = read (4), w = write (2), x = execute (1)

# Change permissions
chmod 755 script.sh          # rwxr-xr-x (owner: read/write/execute, others: read/execute)
chmod +x script.sh           # Add execute permission
chmod -w filename.txt        # Remove write permission
chmod u+x,g-w,o-r file.txt   # Complex permission changes

# Change ownership
chown user:group filename.txt      # Change owner and group
chown user filename.txt            # Change owner only
sudo chown root:root filename.txt  # Change to root (requires sudo)


# PROCESS MANAGEMENT

# View running processes
ps                           # Show current user's processes
ps aux                       # Show all processes (detailed)
ps -ef                       # Alternative detailed view
top                          # Interactive process viewer (q to quit)
htop                         # Enhanced process viewer (if installed)

# Windows processes
tasklist                     # Show running processes
taskmgr                      # Open Task Manager

# Kill processes
kill 1234                    # Kill process with PID 1234
kill -9 1234                 # Force kill process
killall process_name         # Kill all processes by name
pkill process_name           # Kill processes by name pattern

# Windows kill
taskkill /PID 1234           # Kill process by PID
taskkill /IM notepad.exe     # Kill process by name

# Background processes
command &                    # Run command in background
nohup command &              # Run command immune to hangups
jobs                         # List background jobs
fg %1                        # Bring job 1 to foreground
bg %1                        # Send job 1 to background


# NETWORK COMMANDS

# Network information
ping google.com              # Test connectivity
ping -c 4 google.com         # Ping 4 times only
traceroute google.com        # Trace route to destination
netstat -an                  # Show network connections
ifconfig                     # Show network interfaces (macOS/Linux)
ip addr show                 # Show IP addresses (Linux)

# Windows network
ipconfig                     # Show network configuration
ipconfig /all                # Detailed network information
tracert google.com           # Trace route (Windows)

# Download files
wget https://example.com/file.zip        # Download file (Linux)
curl -O https://example.com/file.zip     # Download file (macOS/Linux)
curl -L -o file.zip https://short.url    # Follow redirects and rename

# Test web services
curl https://api.example.com             # Make HTTP request
curl -X POST -d "data" https://api.com   # POST request with data


# SYSTEM INFORMATION

# System details
uname -a                     # System information
whoami                       # Current username
id                           # User and group IDs
uptime                       # System uptime and load
date                         # Current date and time
cal                          # Calendar
which command                # Show command location

# Windows system info
systeminfo                  # Detailed system information
whoami                       # Current username
echo %USERNAME%              # Username via environment variable

# Disk usage
df -h                        # Disk space usage (human readable)
du -sh *                     # Directory sizes in current folder
du -sh /path/to/directory    # Size of specific directory
free -h                      # Memory usage (Linux)

# Windows disk info
dir                          # Basic directory info with sizes


# ENVIRONMENT VARIABLES

# View environment variables
env                          # Show all environment variables
echo $PATH                   # Show specific variable (Unix)
echo $HOME                   # Home directory
printenv PATH                # Alternative way to show variable

# Windows environment
set                          # Show all environment variables
echo %PATH%                  # Show specific variable
echo %USERPROFILE%           # User profile directory

# Set environment variables
export VAR_NAME="value"      # Set variable (current session)
export PATH=$PATH:/new/path  # Add to PATH

# Windows set
set VAR_NAME=value           # Set variable (current session)


# ARCHIVE AND COMPRESSION

# Tar archives
tar -czf archive.tar.gz folder/         # Create compressed archive
tar -xzf archive.tar.gz                 # Extract compressed archive
tar -tzf archive.tar.gz                 # List contents without extracting
tar -xzf archive.tar.gz -C /destination # Extract to specific directory

# Zip files
zip -r archive.zip folder/              # Create zip archive
unzip archive.zip                       # Extract zip archive
unzip -l archive.zip                    # List zip contents

# Windows compression
# Use built-in tools or third-party software like 7-Zip


# TEXT PROCESSING

# Sort and unique
sort filename.txt            # Sort lines alphabetically
sort -n numbers.txt          # Sort numerically
sort -r filename.txt         # Reverse sort
uniq filename.txt            # Remove duplicate lines
sort filename.txt | uniq     # Sort and remove duplicates

# Count
wc filename.txt              # Count lines, words, characters
wc -l filename.txt           # Count lines only
wc -w filename.txt           # Count words only

# Cut and paste
cut -d',' -f1 data.csv       # Extract first column from CSV
cut -c1-10 filename.txt      # Extract characters 1-10 from each line

# Text replacement
sed 's/old/new/g' file.txt   # Replace all occurrences of "old" with "new"
sed -i 's/old/new/g' file.txt # Replace in file (in-place)

# Advanced text processing
awk '{print $1}' file.txt    # Print first column
awk -F',' '{print $2}' data.csv # Print second column of CSV


# REDIRECTION AND PIPES

# Output redirection
command > output.txt         # Redirect output to file (overwrite)
command >> output.txt        # Redirect output to file (append)
command 2> errors.txt        # Redirect errors to file
command > output.txt 2>&1    # Redirect both output and errors

# Input redirection
command < input.txt          # Use file as input

# Pipes (chain commands)
ls -l | grep ".txt"          # List files and filter for .txt files
cat file.txt | grep "error" | wc -l    # Count error lines
ps aux | grep "python"       # Find Python processes
history | grep "git"         # Search command history

# Useful pipe combinations
cat /var/log/apache2/access.log | grep "404" | wc -l    # Count 404 errors
ls -la | sort -k5 -n         # Sort files by size
du -sh * | sort -h           # Sort directories by size


# SHORTCUTS AND PRODUCTIVITY

# Command history
history                      # Show command history
!!                          # Repeat last command
!123                        # Repeat command number 123
!git                        # Repeat last command starting with "git"
Ctrl+R                      # Search command history (interactive)

# Command line editing
Ctrl+A                      # Move to beginning of line
Ctrl+E                      # Move to end of line
Ctrl+U                      # Delete from cursor to beginning
Ctrl+K                      # Delete from cursor to end
Ctrl+W                      # Delete previous word
Alt+F                       # Move forward one word
Alt+B                       # Move backward one word

# Tab completion
[Tab]                       # Auto-complete commands and filenames
[Tab][Tab]                  # Show all possible completions

# Job control
Ctrl+C                      # Interrupt/kill current command
Ctrl+Z                      # Suspend current command
Ctrl+D                      # End input/logout
Ctrl+L                      # Clear screen (same as clear command)


# ALIASES AND FUNCTIONS

# Create aliases
alias ll='ls -la'           # Create shortcut for long listing
alias grep='grep --color=auto'  # Always colorize grep output
alias ..='cd ..'            # Quick parent directory navigation

# View aliases
alias                       # Show all aliases

# Remove alias
unalias ll                  # Remove specific alias

# Functions (more powerful than aliases)
mkcd() {
    mkdir -p "$1" && cd "$1"
}
# Usage: mkcd new/directory/path

# Backup function
backup() {
    cp "$1" "$1.backup-$(date +%Y%m%d)"
}
# Usage: backup important_file.txt


# GIT COMMANDS (Development Essential)

# Repository setup
git init                    # Initialize new repository
git clone https://github.com/user/repo.git  # Clone repository

# Basic workflow
git status                  # Check repository status
git add filename.txt        # Stage specific file
git add .                   # Stage all changes
git add -A                  # Stage all changes including deletions
git commit -m "message"     # Commit with message
git push                    # Push to remote repository
git pull                    # Pull from remote repository

# Branching
git branch                  # List branches
git branch new-feature      # Create new branch
git checkout new-feature    # Switch to branch
git checkout -b new-feature # Create and switch to branch
git merge feature-branch    # Merge branch into current branch
git branch -d feature-branch # Delete branch

# History and information
git log                     # Show commit history
git log --oneline           # Compact commit history
git diff                    # Show unstaged changes
git diff --staged           # Show staged changes
git show HEAD               # Show last commit details


# PACKAGE MANAGERS

# Node.js (npm/yarn)
npm install package-name    # Install package locally
npm install -g package-name # Install package globally
npm list                    # List installed packages
npm outdated                # Check for outdated packages
npm update                  # Update packages
yarn add package-name       # Yarn equivalent of npm install

# Python (pip)
pip install package-name    # Install Python package
pip list                    # List installed packages
pip freeze > requirements.txt  # Save dependencies
pip install -r requirements.txt # Install from requirements

# macOS (Homebrew)
brew install package-name   # Install package
brew list                   # List installed packages
brew update                 # Update Homebrew
brew upgrade                # Upgrade packages

# Linux (apt - Ubuntu/Debian)
sudo apt update             # Update package index
sudo apt install package   # Install package
apt list --installed       # List installed packages
sudo apt remove package    # Remove package


# DEVELOPMENT WORKFLOW COMMANDS

# Project initialization
mkdir my-project && cd my-project  # Create and enter project directory
git init                           # Initialize git repository
npm init -y                        # Initialize package.json
touch README.md .gitignore         # Create essential files

# Server and development
python -m http.server 8000         # Simple HTTP server (Python 3)
python -m SimpleHTTPServer 8000    # Simple HTTP server (Python 2)
php -S localhost:8000              # PHP development server
npm start                          # Start Node.js application
npm run dev                        # Run development script

# File monitoring
tail -f /var/log/apache2/error.log # Monitor log file
watch -n 2 'ls -la'               # Repeat command every 2 seconds
fswatch . | xargs -I{} echo "File changed: {}"  # Watch for file changes

# Database
mysql -u username -p database_name    # Connect to MySQL
psql -U username database_name         # Connect to PostgreSQL
sqlite3 database.db                    # Open SQLite database


# SYSTEM MAINTENANCE

# Disk cleanup
sudo apt autoremove         # Remove unnecessary packages (Ubuntu)
brew cleanup                # Clean up Homebrew cache
npm cache clean --force     # Clear npm cache
docker system prune         # Clean up Docker (if installed)

# Service management (Linux)
sudo systemctl start service_name     # Start service
sudo systemctl stop service_name      # Stop service
sudo systemctl status service_name    # Check service status
sudo systemctl enable service_name    # Enable service at boot

# Log examination
sudo tail -f /var/log/syslog          # System log
sudo journalctl -f                    # Systemd journal
grep "ERROR" /var/log/application.log # Search for errors


# REMOTE ACCESS

# SSH (Secure Shell)
ssh user@hostname           # Connect to remote server
ssh -p 2222 user@hostname   # Connect using specific port
ssh-keygen -t rsa           # Generate SSH key pair
ssh-copy-id user@hostname   # Copy public key to remote server

# SCP (Secure Copy)
scp file.txt user@hostname:/path/to/destination  # Copy file to remote
scp user@hostname:/path/to/file.txt .           # Copy file from remote
scp -r folder user@hostname:/path/              # Copy directory recursively

# RSYNC (efficient file synchronization)
rsync -av source/ destination/                  # Sync directories
rsync -av --delete source/ user@host:/dest/     # Sync with deletion


# ADVANCED TIPS AND TRICKS

# Command substitution
echo "Today is $(date)"                         # Command substitution
files=$(ls *.txt)                              # Store command output

# Conditional execution
command1 && command2                           # Run command2 only if command1 succeeds
command1 || command2                           # Run command2 only if command1 fails
test -f file.txt && echo "File exists"         # Conditional based on file existence

# Loops in command line
for file in *.txt; do echo "Processing $file"; done      # Process all .txt files
while read line; do echo "Line: $line"; done < file.txt  # Read file line by line

# Find and execute
find . -name "*.log" -exec rm {} \;            # Find and delete all .log files
find . -name "*.js" -exec grep -l "TODO" {} \; # Find JS files containing "TODO"

# Useful one-liners
grep -r "function" --include="*.js" .          # Search for "function" in all JS files
find . -type f -name "*.txt" | wc -l           # Count .txt files
ls -la | awk '{print $9}' | grep -v "^$"      # List only filenames
du -sh */ | sort -h                            # Sort directories by size

# Multiple commands
command1; command2; command3                   # Run sequentially regardless of success
(cd /tmp && ls -la)                           # Run commands in subshell

# Background and nohup
nohup long-running-command &                   # Run command immune to logout
screen -S session_name                         # Start screen session
tmux new -s session_name                       # Start tmux session


# TROUBLESHOOTING

# Common issues and solutions
which command               # Check if command exists and its location
echo $PATH                  # Check PATH environment variable
file filename               # Determine file type
ldd binary_file            # Show shared library dependencies (Linux)

# Permission issues
ls -la filename            # Check file permissions
sudo chown $USER:$USER filename  # Take ownership of file
chmod +x script.sh          # Make script executable

# Disk space issues
df -h                       # Check disk space
du -sh * | sort -h          # Find largest directories
sudo lsof +D /path          # Find open files in directory

# Process issues
ps aux | grep process_name  # Find process
kill -9 PID                # Force kill process
sudo netstat -tulpn        # Check port usage

# Memory issues
free -h                     # Check memory usage
top                         # Monitor system resources
sudo dmesg | tail           # Check system messages


# COMMON FILE LOCATIONS

# Configuration files (Linux/macOS)
~/.bashrc                   # Bash configuration
~/.zshrc                    # Zsh configuration
~/.gitconfig                # Git configuration
~/.ssh/config               # SSH configuration
/etc/hosts                  # Host file
/etc/passwd                 # User accounts
/var/log/                   # Log files directory

# Application directories
~/Documents                 # User documents
~/Downloads                 # Downloaded files
~/Desktop                   # Desktop files
/usr/local/bin              # User-installed binaries
/opt/                       # Optional software packages


# PRODUCTIVITY SHORTCUTS BY SHELL

# Bash/Zsh shortcuts
Ctrl+A, Ctrl+E            # Beginning/end of line
Ctrl+R                    # Reverse search history
Ctrl+L                    # Clear screen
Alt+.                     # Insert last argument from previous command

# Fish shell shortcuts
Alt+Up/Down               # Browse command history
Alt+Left/Right            # Move by words
Tab                       # Intelligent autocompletion

# Oh My Zsh plugins (if installed)
# git plugin: automatic git aliases
# z plugin: smart directory jumping
# autosuggestions: command suggestions based on history


# SCRIPTING BASICS

# Shebang lines
#!/bin/bash                # Bash script
#!/usr/bin/env python3     # Python script
#!/usr/bin/env node        # Node.js script

# Basic script structure
#!/bin/bash
set -e                     # Exit on any error
echo "Starting script..."
# Your commands here
echo "Script completed!"

# Make script executable
chmod +x script.sh
./script.sh               # Run script


# WINDOWS-SPECIFIC COMMANDS

# PowerShell equivalents
Get-ChildItem             # ls equivalent
Get-Content file.txt      # cat equivalent
Copy-Item                 # cp equivalent
Move-Item                 # mv equivalent
Remove-Item               # rm equivalent
Get-Process               # ps equivalent
Stop-Process              # kill equivalent

# Windows Command Prompt
dir                       # List directory
cd                        # Change directory
copy                      # Copy files
move                      # Move files
del                       # Delete files
type                      # Display file contents
find "text" file.txt      # Search in file


echo "Terminal Reference Complete!"
echo "Practice these commands daily to become proficient"
echo "Remember: man command_name shows detailed help for any command"
echo "Use command --help or command -h for quick help"