Usage Guide - My Linux Environment

./start_linux.sh

Alpine login: root
Password: [press Enter if no password]

# Check you're in Alpine
cat /etc/os-release

# Check system time
date

# Check network status
ifconfig

# Check disk space
df -h

# Check Alpine version
cat /etc/alpine-release

# Check kernel version
uname -r

# Check installed packages
apk info

# Get system information
uname -a
lsb_release -a  # (if installed)

# Update package database
apk update

# Upgrade all packages
apk upgrade

# Search for a package
apk search vim
apk search -r "python"  # Regex search

# Install packages
apk add vim
apk add openssh curl wget

# Install specific version
apk add vim@latest
apk add "nodejs<18"

# Remove package
apk del vim

# Remove with dependencies
apk del --purge vim

# List installed packages
apk info

# Get info about specific package
apk info vim
apk info -d openssh  # Show description

# Search available packages
apk search                    # List all
apk search -d "text editor"  # Search by description

# Fix package issues
apk fix

# Essential build tools
apk add build-base
apk add gcc g++ make

# Version control
apk add git
apk add mercurial

# Text editors
apk add vim
apk add nano
apk add neovim

# Shells
apk add bash bash-doc
apk add zsh

# Python
apk add python3 py3-pip

# Node.js
apk add nodejs npm

# Ruby
apk add ruby ruby-dev

# Alpine standard directories
/root           # root user home
/home           # regular user homes
/etc            # configuration files
/var            # variable data
/tmp            # temporary files
/opt            # optional software
/usr/local      # user-installed software
/etc/apk        # APK package manager

# List files
ls                      # Basic listing
ls -la                  # Detailed with hidden
ls -lah                 # Same + human-readable
ls -1                   # One file per line
ls -S                   # Sort by size
ls -t                   # Sort by time

# File inspection
file /path/to/file      # Determine file type
stat /path/to/file      # Detailed file info

# Change directory
cd /tmp
cd ..                   # Parent directory
cd ~                    # Home directory
cd -                    # Previous directory

# Create/Remove
mkdir dirname           # Create directory
mkdir -p a/b/c          # Create nested
rmdir dirname           # Remove empty directory
rm filename             # Remove file
rm -rf dirname          # Remove recursive
rm -i file              # Interactive (confirm)

# Copy/Move
cp file1 file2          # Copy file
cp -r dir1 dir2         # Copy directory
mv file1 file2          # Move/rename
mv dir1 dir2            # Move directory

# View file contents
cat file                # Display entire file
more file               # Paginated view
less file               # Scrollable view
head -n 5 file          # First 5 lines
tail -n 5 file          # Last 5 lines
tail -f file            # Follow file (live)

# Search files
grep pattern file       # Search in file
grep -r pattern .       # Search recursive
grep -i pattern file    # Case insensitive
find . -name "*.txt"    # Find by pattern

# View permissions
ls -la

# Permission format: rwxrwxrwx (user|group|other)
# r=read(4) w=write(2) x=execute(1)

# Change permissions
chmod 755 file          # rwxr-xr-x
chmod 644 file          # rw-r--r--
chmod u+x file          # Add execute for user
chmod g-w file          # Remove write from group
chmod o-rwx file        # Remove all from others

# Change ownership
chown user:group file
chown -R user:group dir

# Common combinations
chmod 700 file          # Owner only (rwx------)
chmod 755 file          # Script/executable (rwxr-xr-x)
chmod 644 file          # Regular file (rw-r--r--)

# List running processes
ps                      # Current shell processes
ps aux                  # All processes
ps aux | grep pattern   # Find specific process

# Process info
top                     # Interactive process viewer
htop                    # Enhanced top (if installed)

# Background processes
command &               # Run in background
jobs                    # List background jobs
fg                      # Bring to foreground
bg                      # Resume in background

# Kill processes
kill PID                # Terminate process
kill -9 PID             # Force kill
pkill pattern           # Kill by name

# System info
uname -a                # All system info
uname -s                # Kernel name
uname -r                # Kernel release
uname -m                # Machine hardware name

# CPU info
nproc                   # Number of CPUs
cat /proc/cpuinfo       # CPU details

# Memory info
free -h                 # Memory usage
free -m                 # In megabytes
cat /proc/meminfo       # Detailed memory

# Disk usage
df -h                   # Disk space per filesystem
du -h /path             # Directory size
du -sh /path            # Total directory size

# Uptime
uptime
cat /proc/uptime

# Load average
cat /proc/loadavg

# Current user
whoami                  # Current username
id                      # User ID info
groups                  # Group membership

# List users
cat /etc/passwd         # All users

# Switch user
su                      # Switch to root
su - username           # Switch to user (with env)
exit                    # Exit su session

# Become root (if in sudoers)
sudo command
sudo -s                 # Root shell

# Change password
passwd                  # Change current password
passwd username         # Change user password (as root)

# Service operations
rc-service sshd start   # Start service
rc-service sshd stop    # Stop service
rc-service sshd restart # Restart service
rc-service sshd status  # Check status

# Boot services
rc-update add sshd      # Enable at boot
rc-update del sshd      # Disable at boot
rc-update show          # List boot services

# Manual startup
/etc/init.d/sshd start  # Direct init script

# List all services
rc-service --list

# View network interfaces
ifconfig
ip addr show
ip link show

# View routes
route -n
ip route show

# View DNS
cat /etc/resolv.conf

# View network stats
netstat -an
ss -an                  # Modern equivalent

# Test internet connectivity
ping 8.8.8.8            # Google DNS
ping -c 4 example.com   # Limit to 4 packets

# DNS resolution
nslookup example.com
dig example.com

# Get network info
hostname                # Current hostname
echo $HOSTNAME          # Hostname variable
hostnamectl set-hostname newname  # Change hostname (if available)

# Download files
wget https://example.com/file.tar.gz
curl https://example.com/file

# Network utilities
apk add net-tools           # Add netstat, ifconfig, etc.
apk add curl wget           # HTTP clients
apk add openssh-client      # SSH client
apk add nmap                # Network scanner

# Install git
apk add git

# Configure git
git config --global user.email "you@example.com"
git config --global user.name "Your Name"

# Clone repository
git clone https://github.com/user/repo.git

# Common git tasks
cd repo
git status              # Check status
git add .               # Stage changes
git commit -m "msg"     # Commit
git push                # Push to remote
git pull                # Pull latest
git log                 # View history
git branch -a           # List branches

# Install Python
apk add python3 py3-pip py3-venv

# Create virtual environment
python3 -m venv env
source env/bin/activate

# Install packages
pip install package_name
pip list

# Run Python
python3 script.py

# Interactive Python
python3

# Install Node
apk add nodejs npm

# Check versions
node --version
npm --version

# Create project
mkdir myproject
cd myproject
npm init -y

# Install dependencies
npm install package_name

# Run project
npm start

# Create script
cat > myscript.sh << 'EOF'
#!/bin/sh
echo "Hello, World!"
uname -a
EOF

# Make executable
chmod +x myscript.sh

# Run script
./myscript.sh

# View script
cat myscript.sh

# Edit script
vi myscript.sh

# Install openssh
apk add openssh openssh-doc

# Generate keys (first time)
ssh-keygen -A

# Start SSH server
rc-service sshd start

# Enable at boot
rc-update add sshd

# Connect from host
# On your host machine:
# ssh root@127.0.0.1

# Add user
adduser username

# Add user (non-interactive)
adduser -D username

# Set password
passwd username

# Add to group
addgroup username groupname

# User info
id username
groups username

# Tar archives
tar -czf archive.tar.gz directory/  # Create compressed
tar -xzf archive.tar.gz             # Extract

# Zip files
apk add zip unzip
zip -r archive.zip directory/
unzip archive.zip

# View contents without extracting
tar -tzf archive.tar.gz
unzip -l archive.zip

# Stream editor
sed 's/old/new/' file           # Replace first
sed 's/old/new/g' file          # Replace all
sed '1,5d' file                 # Delete lines 1-5

# Field extraction
awk -F: '{print $1}' /etc/passwd  # Print first field
awk '{print NR, $0}' file         # Print with line numbers

# Filtering
grep pattern file
grep -v pattern file            # Invert match

# Sorting and counting
sort file
sort -n file                    # Numeric sort
uniq file                       # Remove duplicates
wc -l file                      # Count lines

# Check syntax without running
sh -n script.sh

# Debug mode
sh -x script.sh

# Conditional execution
command1 && command2            # command2 if command1 succeeds
command1 || command2            # command2 if command1 fails

# Piping
command1 | command2             # Pipe output
command1 2>&1                   # Redirect stderr to stdout

# Output redirection
command > file                  # Overwrite
command >> file                 # Append
command 2> error.log           # Redirect errors

# Update and upgrade
apk update
apk upgrade

# Check what would change
apk upgrade --dry-run

# Full system update
apk update && apk upgrade

# Install essentials
apk add build-base git curl wget

# Install Python
apk add python3 py3-pip

# Create project directory
mkdir -p ~/projects/myapp
cd ~/projects/myapp

# Initialize git
git init

# Create virtual environment
python3 -m venv env
source env/bin/activate

# Install dependencies
pip install flask
echo "Flask is ready!"

# Install web server
apk add nginx

# Start server
rc-service nginx start

# Enable at boot
rc-update add nginx

# Check status
rc-service nginx status

# Configure
vi /etc/nginx/nginx.conf

# Test configuration
nginx -t

# Create tar backup
tar -czf backup-$(date +%Y%m%d).tar.gz ~/data/

# List backups
ls -lh backup-*.tar.gz

# Verify backup
tar -tzf backup-20250101.tar.gz | head

# Restore from backup
tar -xzf backup-20250101.tar.gz

# Check disk usage
df -h

# Clean package cache
apk cache clean

# Remove unused packages
apk autoremove

# Check for updates
apk update

# Upgrade all packages
apk upgrade

# Check file system
fsck /dev/hda1          # Requires reboot

# System shutdown
shutdown -h now         # Halt
shutdown -r now         # Reboot

# Package might not be installed
apk search command_name

# Install it
apk add package_name

# Or check if it's in PATH
which command_name
echo $PATH

# Make file executable
chmod +x file

# Or run with elevated privileges
su -

# Check disk usage
df -h

# Find large files
find / -size +100M

# Clean cache
apk cache clean

# Check memory
free -h

# Close other processes
ps aux
kill PID

# Check running processes
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