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Reduce PDF Size on Linux With Ghostscript

Have you ever had a PDF file that was unnecessarily large? Whether it’s for emailing, archiving, or simply saving space, reducing the size of a PDF can be incredibly useful. On Linux, one of the most effective tools for this task is gs, short for Ghostscript.

gs is a versatile interpreter for PostScript and PDF files. It can do a lot, but we’re focusing on its ability to optimize PDF files. The key is to use the right combination of options.

The general command structure is:

bash code snippet start

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

bash code snippet end

Let’s break down the most important parts:

  • -sDEVICE=pdfwrite: Specifies that we want to create a PDF file.
  • -dCompatibilityLevel=1.4: Sets the PDF compatibility level. 1.4 is a good balance for older viewers while still allowing some modern features. You can experiment with higher levels (like 1.5, 1.6, etc.) if needed.
  • -dPDFSETTINGS=/screen: This is the crucial option! It controls the level of compression applied. Here are a few common options:
    • /screen: Lowest quality, smallest file size. Good for on-screen viewing.
    • /ebook: Medium quality, good for e-readers and general use.
    • /printer: High quality, suitable for printing.
    • /prepress: Highest quality, intended for professional printing.
  • -dNOPAUSE -dQUIET -dBATCH: These options tell Ghostscript to run non-interactively, suppress informational messages, and exit after processing.
  • -sOutputFile=output.pdf: Specifies the name of the output PDF file.
  • input.pdf: The name of the PDF file you want to compress.

Examples

Compressing for Emailing

Let’s say you have a PDF named original.pdf that’s too large to email. You can use the following command to create a smaller version:

bash code snippet start

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=report.pdf original.pdf

bash code snippet end

This will create a new file named report.pdf with a significantly reduced file size, suitable for emailing.

Compressing for Archiving

For archiving documents where print quality isn’t paramount but readability is desired, use the /ebook setting:

bash code snippet start

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=archive.pdf original.pdf

bash code snippet end

This balances quality and size, making it a good choice for long-term storage.