Prerequisites

SQLite must be available on your system. Install it e.g. via Chocolatey:

choco install sqlite

Alternatively, you can download sqlite3.exe directly from sqlite.org and add it to your PATH.

Create a Database and Table

$DbPath = "C:\temp\books.db"

# Create database and table
sqlite3 $DbPath "CREATE TABLE IF NOT EXISTS books (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    author TEXT NOT NULL,
    read INTEGER DEFAULT 0
);"

Insert Data

sqlite3 $DbPath "INSERT INTO books (title, author, read) VALUES ('Friends, Lovers and the Big Terrible Thing', 'Matthew Perry', 1);"
sqlite3 $DbPath "INSERT INTO books (title, author, read) VALUES ('C# in Depth', 'Jon Skeet', 0);"

Query Data

# List all books
sqlite3 -header -column $DbPath "SELECT * FROM books;"

Output:

id  title                                          author          read
--  ---------------------------------------------  --------------  ----
1   Friends, Lovers and the Big Terrible Thing     Matthew Perry   1
2   C# in Depth                                    Jon Skeet       0

Processing Query Results in PowerShell

The output of sqlite3 can be directly converted into PowerShell variables:

# Use CSV mode for easy parsing
$Results = sqlite3 -csv -header $DbPath "SELECT title, author FROM books WHERE read = 0;"
$Books = $Results | ConvertFrom-Csv

foreach ($Book in $Books) {
    Write-Host "Not yet read: $($Book.title) by $($Book.author)"
}

Update and Delete Data

# Mark book as read
sqlite3 $DbPath "UPDATE books SET read = 1 WHERE title = 'C# in Depth';"

# Delete an entry
sqlite3 $DbPath "DELETE FROM books WHERE id = 2;"

Helper Function for Repeated Queries

To simplify repeated calls, a small wrapper function comes in handy:

function Invoke-Sqlite {
    param(
        [string]$Database,
        [string]$Query
    )
    $Output = sqlite3 -csv -header $Database $Query
    if ($Output) {
        return $Output | ConvertFrom-Csv
    }
}

# Usage
$AllBooks = Invoke-Sqlite -Database $DbPath -Query "SELECT * FROM books;"
$AllBooks | Format-Table

Listing Installed Packages

To see what software is installed via Homebrew, run:

brew list

This command displays all installed formulae (command-line tools and libraries). If you also want to see GUI applications installed via Homebrew Cask, use:

brew list --cask

This will show a list of applications installed using Cask, such as web browsers, terminal emulators, and text editors.

Uninstalling Unnecessary Applications

To remove an installed package, use:

brew uninstall <package-name>

For example, to remove Visual Studio Code:

brew uninstall --cask visual-studio-code

If you want to remove multiple packages at once:

brew uninstall --cask iterm2 kap keka

To remove all installed Cask applications:

brew list --cask | xargs brew uninstall --cask

Cleaning Up

After uninstalling applications, it’s a good idea to free up disk space with:

brew cleanup

This removes outdated versions and unnecessary files. By following these steps, you can efficiently manage your macOS applications using Homebrew, ensuring your system stays clean and optimized.

When you run a shell script on a Unix-like system and see an error like:

zsh: ./script.sh: bad interpreter: /bin/bash^M: no such file or directory

this indicates that your script was saved with Windows line endings (CRLF) instead of Unix line endings (LF). The extra ^M character causes the interpreter path to be misread.

Why It Happens

• Windows vs. Unix: Windows uses CRLF (\r\n) for line breaks, while Unix-like systems use LF (\n).
• Impact on Scripts: The extra carriage return (\r) is appended to the shebang line (e.g., /bin/bash^M), causing the system to fail in locating the correct interpreter.

How to Fix It

1. Using dos2unix

If you have dos2unix installed, simply run:

dos2unix script.sh

This command converts the file to Unix line endings.

1. Using sed

You can also remove carriage returns using sed:

sed -i 's/\r$//' script.sh

This command edits the file in place, removing the \r at the end of each line.

1. Using a Text Editor

Open the script in an editor that supports different line endings (e.g., VS Code, Sublime Text, or Notepad++), and convert the file format to Unix (LF). Save the file afterwards.

By ensuring your shell scripts use Unix line endings, you can avoid interpreter errors and ensure smooth execution across different environments.

1. Update Your Local Repository

Before starting, ensure your repository is up-to-date. If you have any pending changes, commit them and pull the latest updates:

git pull origin main

(Replace main with your branch name if needed.)

1. Create a New Branch for the Subdirectory

Use the subtree split command to extract your subdirectory (e.g., WizzadPlus2022) into a new branch:

git subtree split --prefix=WizzadPlus2022 -b wizzadplus2022-only

• --prefix=WizzadPlus2022: Specifies the directory to extract.
• -b wizzadplus2022-only: Creates a new branch containing only the commits affecting that directory.

1. Set Up a New Repository

Create a new, empty repository on your favorite Git hosting service (GitHub, GitLab, etc.). Note the repository URL (e.g., git@github.com:yourUsername/WizzadPlus2022.git).

1. Push the New Branch to the New Repository

Add the new remote and push your branch:

git remote add wizzadplus2022 <NEW_REPO_URL>
git push wizzadplus2022 wizzadplus2022-only:main

This command pushes your new branch as the main branch in the new repository.

Installing Homebrew on macOS 13 Ventura

To install Homebrew on macOS 13 Ventura, follow these steps: Install Xcode Command Line Tools: Execute:

xcode-select --install

A prompt will appear; click ‘Install’ to proceed.

Install Homebrew: Run:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

This script will download and install Homebrew.

Adding Homebrew to Your PATH To ensure that Homebrew and its installed packages are accessible from the terminal, you need to add Homebrew to your shell’s PATH. This step is crucial for the proper functioning of Homebrew. Here’s how to do it: 1. Determine Your Shell:

echo $SHELL

If the output includes /bin/zsh, you’re using zsh. If it shows /bin/bash, you’re using bash.

Add Homebrew to the PATH: For zsh Users: Open (or create) your .zprofile file:

nano ~/.zprofile

Add the following line to the file:

eval "$(/opt/homebrew/bin/brew shellenv)"

For bash Users: Open (or create) your .bash_profile file:

nano ~/.bash_profile

Add the following line to the file:

eval "$(/opt/homebrew/bin/brew shellenv)"

Apply the Changes: To immediately apply the changes without restarting the terminal, run:

source ~/.zprofile

or

source ~/.bash_profile

depending on your shell.

By following these steps, Homebrew will be added to your PATH, ensuring that you can use the brew command and access the software installed via Homebrew seamlessly.

Verify Installation

After installation, confirm that Homebrew is set up correctly by running:

brew doctor

If everything is properly installed, you’ll see the message “Your system is ready to brew.”

Uninstalling Homebrew

If you need to uninstall Homebrew, execute the following command in Terminal:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/uninstall.sh)"

This command will remove Homebrew and all installed packages from your system.

The quickest ways to shut down your Linux system via terminal:

• shutdown now - safest method, properly saves data
• poweroff - short command, similar to shutdown now
• init 0 - classic Unix command, works on all systems
• halt - stops all processes and system

Create Custom Alias

To set up a convenient shutdown alias:

1. Open .bashrc:

   nano ~/.bashrc
   

2. Add at the end:

   alias sd='shutdown now'
   

3. Save file: CTRL + O, ENTER, CTRL + X
4. Reload .bashrc:

   source ~/.bashrc
   

   Now you can simply type sd to shutdown your system. Pro tip: Consider using alias sd=’sudo shutdown now’ if you always need root privileges.

Prerequisites

• Run PowerShell or Command Prompt as Administrator
• Installation directory: C:\ProgramData\chocolatey

Essential Commands

Installation & Updates

# Install a package
choco install <package-name>

# Update a specific package
choco upgrade <package-name>

# Update all packages
choco upgrade all -y

Package Management

# List installed packages
choco list

# Check for outdated packages
choco outdated

# Search for packages
choco search <package-name>

# Get package information
choco info <package-name>

# Uninstall a package
choco uninstall <package-name>

Example: Managing Terraform

# Install Terraform
choco install terraform

# Check Terraform version
terraform --version

# or
choco list terraform

# Update Terraform
choco upgrade terraform

Tips

1. Use -y flag to automatically confirm actions
2. Pin important packages to prevent automatic updates:
3. Keep Chocolatey updated:
4. Restart terminal after installing new packages
5. Use --what-if to preview changes before execution

Understanding Shims

Chocolatey uses shims to make command-line programs accessible globally. A shim is a small file that redirects to the actual executable of an installed program. They are automatically created in C:\ProgramData\chocolatey\bin. Benefits of shims:

• Makes commands available immediately in any terminal
• Allows running programs without knowing their exact installation path
• Enables seamless updates without changing PATH variables Example: When you install Terraform via Chocolatey, it creates a shim that allows you to run terraform from any location, while the actual executable might be in C:\ProgramData\chocolatey\lib\terraform\tools.

1. Check Firewall Status

sudo ufw status

sudo ufw status verbose

sudo ufw status numbered

2. Install and Enable UFW

# Check if installed
dpkg -l | grep ufw
# or

which ufw

# Install if needed
sudo apt update
sudo apt install ufw

# Enable firewall
sudo ufw enable

3. Basic UFW Configuration

# Default policies
sudo ufw default deny incoming
sudo ufw default allow outgoing

# Common services
sudo ufw allow ssh        # Port 22
sudo ufw allow 80/tcp     # HTTP
sudo ufw allow 443/tcp    # HTTPS

4. System Security Check Commands

# Check open ports
sudo ss -tulpn

# Check login attempts
sudo last
sudo grep "Failed password" /var/log/auth.log

# Check sudo usage
sudo grep "sudo" /var/log/auth.log

5. Enable Automatic Security Updates

sudo apt install unattended-upgrades
sudo dpkg-reconfigure --priority=low unattended-upgrades

6. Daily Security Check Script

Create a script in /etc/cron.daily/security-check that:

• Monitors failed login attempts
• Checks network connections
• Tracks system resources
• Rotates logs (keeps last 10 backups)
• Creates daily reports in /var/log/security-check.log

Notes:

• Default Ubuntu installation doesn’t enable UFW by default
• Basic system is secure even without UFW if no services are installed
• Monitor auth.log for suspicious activities
• GUI configuration available through GUFW: sudo apt install gufw
• Regularly check system logs
• Keep system updated: sudo apt update && sudo apt upgrade
• Monitor open ports and running services

Which shell am I using?

Check your current shell using any of these commands:

echo $SHELL      # Shows path to default shell

echo $0         # Shows shell name

cat /etc/shells # Lists all available shells

Changing your shell

Change your default shell using:

chsh -s /bin/zsh  # Change to ZSH

chsh -s /bin/bash # Change to Bash

Changes take effect after next login.

Shell Configuration Files

Key configuration files and their purposes:

1. ~/.bashrc
   • For interactive non-login shells
   • Contains: aliases, functions, prompt settings
   • Used in most terminal windows you open
2. ~/.profile
   • For login shells
   • Contains: environment variables, PATH settings
   • Read by multiple shells, not just bash
3. /etc/passwd
   • Stores default shell for each user
   • Format: username:x:uid:gid:comment:home:shell
   • Don’t edit directly; use chsh instead

Loading Order

Login Shell:

1. /etc/profile
2. First found of: ~/.profile, ~/.bash_login, or ~/.bash_profile
3. On exit: ~/.bash_logout

Non-Login Shell (regular terminal):

1. /etc/bash.bashrc
2. ~/.bashrc

On Ubuntu, ~/.bashrc is the main configuration file you’ll work with for most shell customizations.

$targetPath = "F:\Downloads\Target"

$newCreationTime = "2001-09-11 00:00:00"

Get-ChildItem -Path $targetPath -Filter *.jpg | ForEach-Object {
    $_.CreationTime = $newCreationTime
    Write-Host "CreationTime for file $($_.Name) was changed to $newCreationTime"
}

You can also change other timestamps like LastWriteTime or LastAccessTime by using the corresponding property:

$_.LastWriteTime = $newCreationTime