The cpdf command is a tool used for manipulating PDF files. It provides various functionalities such as selecting specific pages, merging, splitting, encrypting, decrypting, and more. This article will illustrate each of these use cases with examples.

Use case 1: Select pages from a source document and write to a destination document

Code:

cpdf path/to/source_document.pdf 1-3,6 -o path/to/destination_document.pdf

Motivation: This use case is useful when you want to extract specific pages from a PDF document and create a new document containing only those pages. For example, if you have a large PDF file but only need a few specific pages, you can use this command to extract and save them separately.

Explanation:

• cpdf: The command itself.
• path/to/source_document.pdf: The path to the source PDF document from which pages need to be selected.
• 1-3,6: The page range to select from the source document. In this example, pages 1, 2, 3, and 6 will be selected.
• -o path/to/destination_document.pdf: The output option to specify the path and filename for the destination document.

Example output: The command will create a new PDF document named destination_document.pdf in the specified output path. This document will contain only pages 1, 2, 3, and 6 from the source document.

Use case 2: Merge two documents into a new one

Code:

cpdf -merge path/to/source_document_one.pdf path/to/source_document_two.pdf -o path/to/destination_document.pdf

Motivation: Merging multiple PDF documents into a single document is often required, especially when you have separate files that need to be combined for easier distribution or organization. This use case allows you to combine two PDF documents into a new one.

Explanation:

• cpdf: The command itself.
• -merge: The option to indicate that the command should merge the specified documents.
• path/to/source_document_one.pdf and path/to/source_document_two.pdf: The paths to the two source PDF documents that you want to merge.
• -o path/to/destination_document.pdf: The output option to specify the path and filename for the destination document.

Example output: The command will create a new PDF document named destination_document.pdf in the specified output path. This document will contain all the pages from both source_document_one.pdf and source_document_two.pdf.

Use case 3: Show the bookmarks of a document

Code:

cpdf -list-bookmarks path/to/document.pdf

Motivation: Bookmarks in a PDF document provide a convenient way to navigate through the document’s content. When working with PDF files that have bookmarks, it can be helpful to view a list of all the bookmarks and their hierarchical structure. This use case allows you to list the bookmarks of a PDF document.

Explanation:

• cpdf: The command itself.
• -list-bookmarks: The option to instruct the command to display the bookmarks of the specified document.
• path/to/document.pdf: The path to the PDF document for which you want to view the bookmarks.

Example output: The command will display a list of bookmarks present in the specified PDF document, along with their hierarchical structure.

Use case 4: Split a document into ten-page chunks

Code:

cpdf -split path/to/document.pdf -o path/to/chunk%%%.pdf -chunk 10

Motivation: Splitting a large PDF file into smaller chunks can be useful when you want to divide a document into more manageable sections. This use case allows you to split a PDF document into ten-page chunks and save them as separate files.

Explanation:

• cpdf: The command itself.
• -split: The option to split the specified document into chunks.
• path/to/document.pdf: The path to the PDF document that needs to be split.
• -o path/to/chunk%%%.pdf: The output option to specify the naming pattern for the resulting chunks. The % symbols are replaced with a sequential number for each chunk.
• -chunk 10: The option to specify the number of pages in each chunk. In this example, each chunk will contain ten pages.

Example output: The command will split the document.pdf file into chunks of ten pages each and save them as separate PDF files named chunk001.pdf, chunk002.pdf, and so on.

Use case 5: Encrypt a document using 128bit encryption

Code:

cpdf -encrypt 128bit fred joe path/to/source_document.pdf -o path/to/encrypted_document.pdf

Motivation: Encrypting a PDF document with a password adds a layer of security to the file, protecting its contents from unauthorized access. This use case allows you to encrypt a PDF document using 128-bit encryption and specify owner and user passwords.

Explanation:

• cpdf: The command itself.
• -encrypt 128bit: The option to enable encryption using 128-bit encryption.
• fred: The owner password. This password provides full control over the document, allowing operations like editing or printing.
• joe: The user password. This password restricts certain operations in the document, such as printing or copying.
• path/to/source_document.pdf: The path to the PDF document that needs to be encrypted.
• -o path/to/encrypted_document.pdf: The output option to specify the path and filename for the encrypted document.

Example output: The command will create a new encrypted PDF document named encrypted_document.pdf in the specified output path. To open the document, the user will need to enter the user password specified (joe in this example), and the owner password (fred) provides additional permissions.

Use case 6: Decrypt a document using the owner password

Code:

cpdf -decrypt path/to/encrypted_document.pdf owner=fred -o path/to/decrypted_document.pdf

Motivation: Decrypting a password-protected PDF document allows you to remove the encryption and regain full access to its contents. This use case enables you to decrypt a document using the owner password provided during encryption.

Explanation:

• cpdf: The command itself.
• -decrypt: The option to decrypt the specified document.
• path/to/encrypted_document.pdf: The path to the password-protected PDF document that needs to be decrypted.
• owner=fred: The owner password used during encryption. This password grants full control over the document and is required to decrypt it.
• -o path/to/decrypted_document.pdf: The output option to specify the path and filename for the decrypted document.

Example output: The command will create a new decrypted PDF document named decrypted_document.pdf in the specified output path. The resulting document will no longer require a password to access or perform any operations.

Use case 7: Show the annotations of a document

Code:

cpdf -list-annotations path/to/document.pdf

Motivation: Annotations in a PDF document can include elements such as comments, text highlights, or graphic shapes. When working with PDF files that contain annotations, it can be helpful to view a list of all the annotations present. This use case allows you to display the annotations of a PDF document.

Explanation:

• cpdf: The command itself.
• -list-annotations: The option to instruct the command to display the annotations of the specified document.
• path/to/document.pdf: The path to the PDF document for which you want to view the annotations.

Example output: The command will display a list of annotations present in the specified PDF document, including information about their type, position, and content.

Use case 8: Create a new document with additional metadata

Code:

cpdf -set-metadata path/to/metadata.xml path/to/source_document.pdf -o path/to/destination_document.pdf

Motivation: Adding metadata to a PDF file can provide information about the document, such as author, title, or keywords. This use case allows you to create a new PDF document by adding additional metadata from an XML file to an existing document.

Explanation:

• cpdf: The command itself.
• -set-metadata: The option to set the metadata of the specified document.
• path/to/metadata.xml: The path to the XML file containing the metadata to be added to the document.
• path/to/source_document.pdf: The path to the PDF document to which the metadata will be added.
• -o path/to/destination_document.pdf: The output option to specify the path and filename for the destination document.

Example output: The command will create a new PDF document named destination_document.pdf in the specified output path. This document will contain the contents of the source_document.pdf file along with the additional metadata specified in the XML file.

Conclusion:

The cpdf command provides a wide range of functionality for manipulating PDF files. Whether you need to extract specific pages, merge documents, encrypt or decrypt files, or perform other actions, cpdf offers a versatile set of options to meet your requirements. By following the examples provided in this article, you will be able to utilize the cpdf command effectively for your PDF manipulation needs.