How to merge multiple PDF files into one PDF in Linux ?

To merge multiple PDF files into a single PDF on Linux, you can use one of the following tools:

1. Using pdftk (PDF Toolkit)

Installation:

sudo apt install pdftk-java  # Debian/Ubuntu
sudo dnf install pdftk       # Fedora

Merge PDFs:

pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf

• Wildcard Support:

  pdftk *.pdf cat output merged.pdf  # Merges all PDFs in the current directory

2. Using pdfunite (from Poppler Utils)

Installation:

sudo apt install poppler-utils  # Debian/Ubuntu
sudo dnf install poppler-utils  # Fedora

Merge PDFs:

pdfunite file1.pdf file2.pdf file3.pdf merged.pdf

3. Using Ghostscript

Installation (usually preinstalled):

sudo apt install ghostscript  # If missing

Merge PDFs:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=merged.pdf file1.pdf file2.pdf file3.pdf

4. Using a GUI Tool (e.g., PDF Arranger)

Installation:

sudo apt install pdfarranger  # Debian/Ubuntu
sudo flatpak install com.github.pdfarranger  # Flathub

Usage: Open PDF Arranger, import files, reorder pages, and export as a merged PDF.

Key Notes

• Order Matters: Files are merged in the order they appear in the command.
• Large Files: Ghostscript handles complex PDFs better but may alter formatting.
• Security: Merging password-protected/encrypted PDFs may require decryption first.

Example Workflow

# Merge specific files (pdftk)
pdftk chapter1.pdf chapter2.pdf appendix.pdf cat output book.pdf

# Merge all PDFs in a directory (pdfunite)
pdfunite *.pdf combined.pdf

Choose pdftk/pdfunite for simplicity or Ghostscript for advanced PDF manipulation.