How to remove metadata from pdf on Linux Ubuntu

Install exiftool:

apt install exiftool

Remove the metadata from "thefile.pdf":

exiftool -all= thefile.pdf

Warning: [minor] ExifTool PDF edits are reversible. Deleted tags may be recovered! - thefile.pdf 1 image files updated

Metadata, in the context of PDFs, refers to a set of data that describes and gives information about other data. Essentially, it's data about the PDF that isn't necessarily visible when you open the document but can be extracted using specific tools or software. This might include information such as the author, document properties, editing history, and even comments.

Here are some of the benefits and security reasons to consider removing metadata from a PDF:

Privacy Protection: Metadata can contain personal information, such as the document's author, the software used to create it, and the system or computer on which it was created. By removing this information, you can protect your privacy, especially if the PDF will be shared publicly.
Confidentiality: In a corporate environment, metadata might reveal details about internal processes, review workflows, or internal comments. This could provide competitors with unintended insights.
Professionalism: Stray comments, annotations, or previous versions of the document can look unprofessional if unintentionally shared. Clean PDFs without unnecessary metadata present a more polished image.
Reduces File Size: Metadata, especially when accumulated over time or with embedded comments and annotations, can add to the file size. By removing unnecessary metadata, the PDF might become smaller and easier to share or upload.
Protect Intellectual Property: Metadata might reveal how a document was created, who worked on it, and other insights that could be of value to competitors or adversaries.
Avoid Accidental Disclosure: In legal settings, it's imperative not to disclose more than intended. Metadata can sometimes contain privileged or confidential information that isn't meant for the opposing counsel or the public.
Mitigate Security Risks: Some metadata, especially if embedded with links or scripts, can be a vector for security vulnerabilities. Cleaning up a PDF can be part of a broader strategy to maintain cybersecurity hygiene.
Standardization: For organizations that deal with a large volume of documents, standardizing the process of cleaning up metadata can ensure that all shared documents meet a consistent standard of privacy and professionalism.
Avoid Digital Footprints: If you're a researcher, activist, or anyone concerned about leaving a digital footprint, removing metadata is essential. It ensures that the origins of a document and its path of creation and modification remain hidden.
Regulatory Compliance: Certain industries or sectors have stringent rules about data protection and privacy. In some cases, it might be a regulatory requirement to strip metadata from documents before sharing.