Large PDF files are common. Scanned documents, images, and embedded fonts increase file size fast. This makes sharing, uploading, and emailing harder.

Ghostscript offers a simple way to reduce PDF file size using the command line. It is free, open source, and widely available on Linux systems.

This guide explains how to compress PDFs using Ghostscript with clear examples.

What Is Ghostscript?

Ghostscript is a command-line tool used to process PDF and PostScript files. It is often used in printing workflows and document automation.

Ghostscript works on Linux, macOS, and Windows. It runs offline and does not upload files.

Installing Ghostscript

Most Linux distributions include Ghostscript in their repositories.

Ubuntu and Debian

sudo apt install ghostscript

Fedora

sudo dnf install ghostscript

Arch Linux

sudo pacman -S ghostscript

After installation, check the version:

gs --version

Basic PDF Compression Command

Use the following command to compress a PDF file:

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

This command creates a new PDF with a smaller file size.

PDFSETTINGS Explained

Ghostscript includes preset quality levels.

PDFSETTINGS	Quality Level	Best Use Case
/screen	Low	Email, chat, and quick sharing
/ebook	Medium	Reading on phones, tablets, and laptops
/printer	High	Home and office printing
/prepress	Very high	Professional and commercial printing
/default	Balanced	General purpose use

Checking File Size

Check the file size before and after compression:

ls -lh *.pdf

Scanned PDFs usually shrink more than text-only files.

FAQ

• Does Ghostscript reduce image quality?
  Yes. Lower presets reduce image resolution to save space.

• Is Ghostscript safe for private documents?
  Yes. It works offline and never uploads files.

• Can Ghostscript compress scanned PDFs?
  Yes. Scanned PDFs often see the largest size reduction.

• Does Ghostscript change text quality?
  Text remains clear in most presets, especially ebook and printer modes.

Conclusion

Ghostscript provides a reliable way to reduce PDF file size on Linux. It works offline, respects privacy, and fits well into command-line workflows.