Linux_Commands_CyberPatriot.txt

# Linux Commands for CyberPatriot: Debian, Fedora, and Red Hat Distros

## User Management

### Adding and Managing Users
- **Debian/Ubuntu**:
  sudo adduser <username>
- **Fedora/Red Hat**:
  sudo useradd <username>
  sudo passwd <username>

#### Deleting Users
- **All Distros**:
  sudo userdel <username>
  sudo rm -r /home/<username>  # Remove user's home directory

#### Adding Users to Groups
- **Debian/Ubuntu**:
  sudo usermod -aG <groupname> <username>
- **Fedora/Red Hat**:
  sudo usermod -a -G <groupname> <username>

## Package Management

### Updating the System
- **Debian/Ubuntu**:
  sudo apt update && sudo apt upgrade -y
- **Fedora/Red Hat**:
  sudo dnf update -y

### Installing and Removing Packages
#### Installing a Package
- **Debian/Ubuntu**:
  sudo apt install <package-name>
- **Fedora/Red Hat**:
  sudo dnf install <package-name>

#### Removing a Package
- **Debian/Ubuntu**:
  sudo apt remove <package-name>
- **Fedora/Red Hat**:
  sudo dnf remove <package-name>

## Firewall Configuration

### Checking Firewall Status
- **All Distros**:
  sudo ufw status  # For Debian/Ubuntu (if UFW is installed)
  sudo firewall-cmd --state  # For Fedora/Red Hat

### Enabling and Disabling the Firewall
- **Debian/Ubuntu**:
  sudo ufw enable
  sudo ufw disable
- **Fedora/Red Hat**:
  sudo systemctl start firewalld
  sudo systemctl stop firewalld

### Allowing or Blocking Ports
- **Debian/Ubuntu**:
  sudo ufw allow <port>/tcp
  sudo ufw deny <port>/tcp
- **Fedora/Red Hat**:
  sudo firewall-cmd --add-port=<port>/tcp --permanent
  sudo firewall-cmd --remove-port=<port>/tcp --permanent
  sudo firewall-cmd --reload

## System Monitoring

### Checking System Resources
- **All Distros**:
  top
  htop  # If installed

### Monitoring Disk Usage
- **All Distros**:
  df -h
  du -sh <directory>

### Viewing Open Network Connections
- **All Distros**:
  netstat -tuln  # May need to install `net-tools`
  ss -tuln       # Modern alternative

## Log Management

### Viewing System Logs
- **All Distros**:
  sudo journalctl -xe
  sudo less /var/log/syslog  # Debian/Ubuntu
  sudo less /var/log/messages  # Fedora/Red Hat

### Clearing Logs
- **All Distros**:
  sudo truncate -s 0 /var/log/<logfile>

## Permissions and Ownership

### Changing Ownership
- **All Distros**:
  sudo chown <user>:<group> <file/directory>

### Modifying Permissions
- **All Distros**:
  sudo chmod <permissions> <file/directory>

## Networking

### Displaying IP Addresses
- **All Distros**:
  ip addr

### Testing Network Connectivity
- **All Distros**:
  ping <hostname/IP>

## Miscellaneous Tasks

### Searching for Files
- **All Distros**:
  find / -name <filename>

### Checking Kernel Version
- **All Distros**:
  uname -r

### Scheduling a Task
- **All Distros**:
  crontab -e