PDF Tools

Manipulate PDF files using command-line tools.

Setup

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

# macOS
brew install qpdf pdftk ghostscript poppler

Merge PDFs

# Merge multiple PDFs
qpdf --empty --keep-temporary-files page1.pdf page2.pdf page3.pdf -- merged.pdf

# With pdftk
pdftk page1.pdf page2.pdf page3.pdf cat output merged.pdf

# Merge all PDFs in directory
pdftk *.pdf cat output all_merged.pdf

Split PDFs

# Extract pages 1-5
qpdf input.pdf --pages . 1-5 -- output.pdf

# Extract single page
pdftk input.pdf cat 3 output page3.pdf

# Split into individual pages
pdftk input.pdf burst output page_%d.pdf

# Extract range
qpdf input.pdf --pages . 5-10 -- extracted.pdf

Compress PDF

# Compress with Ghostscript (best quality)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook \
   -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed.pdf input.pdf

# PDF settings options:
# /screen   - 72 dpi, smallest size, lowest quality
# /ebook    - 150 dpi, medium size, good quality
# /printer  - 300 dpi, larger size, high quality
# /prepress - 300 dpi, highest quality

# Quick compress with qpdf
qpdf --compress-streams=y --recompress-flate input.pdf compressed.pdf

Rotate PDF

# Rotate all pages 90 degrees clockwise
pdftk input.pdf cat 1-endright output rotated.pdf

# Rotate specific pages
qpdf input.pdf --rotate=+90:1,3,5 output.pdf

# Rotation options: +90, +180, +270, -90

Add Watermark

# Add text watermark with pdftk
pdftk input.pdf background watermark.pdf output watermarked.pdf

# Create watermark PDF first
echo "DRAFT" | enscript -B -f Courier-Bold100 -o - | ps2pdf - watermark.pdf

Password Protect

# Add password (owner + user)
qpdf --encrypt user_pass owner_pass 256 -- input.pdf protected.pdf

# With pdftk
pdftk input.pdf output protected.pdf encrypt_128bit owner_pw owner_pass user_pw user_pass

Remove Password

# Remove password (requires password)
qpdf --password=yourpass --decrypt protected.pdf unlocked.pdf

# With pdftk
pdftk protected.pdf input_pw yourpass output unlocked.pdf

PDF to Images

# Convert PDF to images (each page)
pdftoppm input.pdf output -png

# Specific page
pdftoppm -f 1 -l 1 input.pdf output -png

# Set resolution (DPI)
pdftoppm -rx 300 -ry 300 input.pdf output -png

Images to PDF

# Convert images to PDF
convert image1.png image2.png output.pdf

# Or with img2pdf (better quality)
img2pdf image1.png image2.png -o output.pdf

Extract Text

# Extract text from PDF
pdftotext input.pdf output.txt

# Keep layout
pdftotext -layout input.pdf output.txt

# Extract from specific pages
pdftotext -f 1 -l 5 input.pdf output.txt

Remove Metadata

# Strip all metadata
qpdf --linearize input.pdf clean.pdf
exiftool -all:all= clean.pdf

# Or with Ghostscript
gs -sDEVICE=pdfwrite -dNOPAUSE -dQUIET -dBATCH \
   -sOutputFile=clean.pdf input.pdf

Tips

• Use qpdf for most operations (faster, more reliable)
• Use pdftk for complex page manipulations
• Use Ghostscript for compression
• Always backup before modifying important PDFs

Triggers

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