🗜️ Compress PDF - Bash Script for Windows

A simple Bash script to compress PDF files on Windows.

It works by iteratively downsampling the resolution of images within the PDF to meet a desired target file size.

✨ Features

• Target Size Compression: Attempts to compress a PDF to a specified target size in kilobytes.
• Iterative Approach: Starts with a higher image resolution and gradually reduces it until the target file size is achieved.
• Safe: Creates a new compressed file (<filename>_compressed.pdf) and never modifies the original.
• Customizable: Easily change the target file size, and tweak resolution parameters within the script.

📋 Requirements

This script is designed to run on Windows within a Bash environment.

🐚 Bash Shell for Windows

• Git Bash (Recommended, comes with Git for Windows).

👻 Ghostscript

• Download and Install: You must have the 64-bit version of Ghostscript installed. You can download it from the official website: Ghostscript - Releases - pick the latest Win 64bit AGPL release.

• Test the Installation: After running the .exe installation file and completing the installation process, open a new Git Bash or Command Prompt window and run the following command to verify that Ghostscript is accessible:

  gswin64c --version

  If it prints a version number, you are all set!

🚀 Script Installation

1. Download the compress-pdf.sh script to a folder on your computer.
2. Make the script executable by running the following command in your Bash terminal:

   chmod +x compress-pdf.sh

💡 Optional: Create an Alias

For easier access from any directory, you can create an alias in your shell's configuration file (.bashrc or .bash_profile).

1. Open ~/.bashrc or ~/.bash_profile in a text editor.
2. Add the following line, replacing ~/path/to/ with the actual path to the script(~ points to the folder ~/Users/<UserName>):

   alias cp_pdf='~/path/to/compress-pdf.sh'

   • The ~ character is a shortcut for your user's home directory (e.g., /c/Users/YourName).
   • For example, if you saved the script in C:\Users\YourName\Scripts, the path in Git Bash would be ~/Scripts/compress-pdf.sh.
   • If you are unsure where your .bashrc file is located, you can run find ~ -maxdepth 1 -name ".bashrc" from your terminal to find it.
3. Save the file and restart your terminal or run source ~/.bashrc.

▶️ Usage

Run the script from your Bash terminal, providing the name of the PDF file without the .pdf extension.

Usage: ./compress-pdf.sh [options] <filename>

⚙️ Options

Flag	Argument	Description
-s	<filesize>	Target file size in KB (default: 2000).
-h		Show the help message.

Important:

• Options must come before the filename.
• The script must be run from the same directory as the PDF file.

📝 Examples

1. Compress with default settings:

Compresses My Document.pdf to a target size of 2000 KB.

./compress-pdf.sh "My Document"

2. Compress to a specific size:

Compresses Another Presentation.pdf to a target size of 800 KB.

./compress-pdf.sh -s 800 "Another Presentation"

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