pdftk-server

SKILL.md

PDFtk Server

PDFtk Server is a command-line tool for working with PDF documents. It can merge, split, rotate, encrypt, decrypt, watermark, stamp, fill forms, extract metadata, and manipulate PDFs in a variety of ways.

When to Use This Skill

Merging or joining multiple PDF files into one

Splitting or bursting a PDF into individual pages

Rotating PDF pages

Encrypting or decrypting PDF files

Filling PDF form fields from FDF/XFDF data

Applying background watermarks or foreground stamps

Extracting PDF metadata, bookmarks, or form field information

Repairing corrupted PDF files

Attaching or extracting files embedded in PDFs

Removing specific pages from a PDF

Collating separately scanned even/odd pages

Compressing or decompressing PDF page streams

Prerequisites

PDFtk Server must be installed on the system

Windows: winget install --id PDFLabs.PDFtk.Server

macOS: brew install pdftk-java

Linux (Debian/Ubuntu): sudo apt-get install pdftk

Linux (Red Hat/Fedora): sudo dnf install pdftk

Access to a terminal or command prompt

Verify installation by running pdftk --version

Step-by-Step Workflows

Merge Multiple PDFs

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

Using handles for more control:

pdftk A=file1.pdf B=file2.pdf cat A B output merged.pdf

Split a PDF into Individual Pages

pdftk input.pdf burst

Extract Specific Pages

Extract pages 1-5 and 10-15:

pdftk input.pdf cat 1-5 10-15 output extracted.pdf

Remove Specific Pages

Remove page 13:

pdftk input.pdf cat 1-12 14-end output output.pdf

Rotate Pages

Rotate all pages 90 degrees clockwise:

pdftk input.pdf cat 1-endeast output rotated.pdf

Encrypt a PDF

Set an owner password and a user password with 128-bit encryption (default):

pdftk input.pdf output secured.pdf owner_pw mypassword user_pw userpass

Decrypt a PDF

Remove encryption using the known password:

pdftk secured.pdf input_pw mypassword output unsecured.pdf

Fill a PDF Form

Populate form fields from an FDF file and flatten to prevent further edits:

pdftk form.pdf fill_form data.fdf output filled.pdf flatten

Apply a Background Watermark

Place a single-page PDF behind every page of the input (input should have transparency):

pdftk input.pdf background watermark.pdf output watermarked.pdf

Stamp an Overlay

Place a single-page PDF on top of every page of the input:

pdftk input.pdf stamp overlay.pdf output stamped.pdf

Extract Metadata

Export bookmarks, page metrics, and document information:

pdftk input.pdf dump_data output metadata.txt

Repair a Corrupted PDF

Pass a broken PDF through pdftk to attempt automatic repair:

pdftk broken.pdf output fixed.pdf

Collate Scanned Pages

Interleave separately scanned even and odd pages:

pdftk A=even.pdf B=odd.pdf shuffle A B output collated.pdf

Troubleshooting

Issue
Solution

pdftk command not found
Verify installation; check that pdftk is in your system PATH

Cannot decrypt PDF
Ensure you are providing the correct owner or user password via input_pw

Output file is empty or corrupt
Check input file integrity; try running pdftk input.pdf output repaired.pdf first

Form fields not visible after fill
Use the flatten flag to merge fields into the page content

Watermark not appearing
Ensure the input PDF has transparent regions; use stamp for opaque overlays

Permission denied errors
Check file permissions on input and output paths

References

Bundled reference documents in the references/ folder:

pdftk-man-page.md - Complete manual reference with all operations, options, and syntax

pdftk-cli-examples.md - Practical command-line examples for common tasks

download.md - Installation and download instructions for all platforms

pdftk-server-license.md - PDFtk Server licensing information

third-party-materials.md - Third-party library licenses