pdf-manipulation

PDF Manipulation Skill

Merge, split, extract, redact, and transform PDF files using free command-line tools and libraries. Covers common PDF operations for document automation workflows.

When to use

• Merge multiple PDFs into one document
• Split large PDFs into separate files or page ranges
• Extract text, images, or specific pages
• Redact sensitive information
• Add watermarks, passwords, or metadata
• Convert PDFs to images or other formats

Required tools

• pdftk — Swiss Army knife for PDF manipulation (merge, split, rotate, encrypt)
• qpdf — PDF transformation and encryption (linearize, decrypt, repair)
• pdftotext / pdfimages — Part of poppler-utils (extract text and images)
• ghostscript (gs) — Advanced PDF processing, compression, and conversion

Installation

# Ubuntu/Debian
sudo apt-get install pdftk qpdf poppler-utils ghostscript

# macOS (Homebrew)
brew install pdftk-java qpdf poppler ghostscript

# For Node.js: npm i pdf-lib (pure JS, no system deps)
# For Python: pip install PyPDF2 pypdf

Skills

Merge PDFs

# Using pdftk (preserves bookmarks, forms)
pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf

# Using ghostscript (better compression)
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=merged.pdf file1.pdf file2.pdf file3.pdf

# Using qpdf (preserves structure)
qpdf --empty --pages file1.pdf file2.pdf file3.pdf -- merged.pdf

Node.js (pdf-lib):

const { PDFDocument } = require('pdf-lib');
const fs = require('fs');

async function mergePDFs(files, output) {
  const mergedPdf = await PDFDocument.create();
  
  for (const file of files) {
    const pdfBytes = fs.readFileSync(file);
    const pdf = await PDFDocument.load(pdfBytes);
    const pages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
    pages.forEach(page => mergedPdf.addPage(page));
  }
  
  const mergedBytes = await mergedPdf.save();
  fs.writeFileSync(output, mergedBytes);
}

// mergePDFs(['file1.pdf', 'file2.pdf'], 'merged.pdf');