qpdf VS HomeBrew

QPDF is a CLI tool that performs content-preserving transformations on PDF files. We have another tool for managing files!

Given how well Preview.app and Safari work for viewing >99% of PDFs I actually encounter in the wild, this article makes Apple's engineering decisions look good.

It also confirms many suspicions I've had over the years that have led me to, e.g., running all PDFs from questionable sources through VirusTotal before viewing on platforms where I wouldn't normally run antivirus software.

The original article also confirms my suspicions that this step is inadequate:

Because the Launch action can be considered as a danger- ous feature, we conducted a large-scale evaluation of 294,586 PDF documents downloaded from the Internet, in order to research if there are any legitimate use cases at all. Of those documents, only 532 files (0.18%) contained a Launch action. While none of the files was classified as malicious according to the VirusTotal database, we conclude that the Launch action is rarely used in the wild and its support should be removed by PDF implementations as well as the standard.

Incidentally, the Launch action is still present in the most recent version of the PDF standard[1], with only OS-specific launch parameters deprecated (which include passing arguments to the launched executable, so eliminating the deprecated feature is still a significant security gain).

Finally, I'm both personally and professionally curious about how the non-DoS examples in this articles may apply to non-viewer PDF tools and libraries like qpdf[2] and Ghostscript's original and recently reimplemented PDF interpreters[3].

[1] https://pdfa.org/resource/iso-32000-pdf/

(registration required, but at least the base standard is available at no cost; sadly, important incorporated standards like ISO 21757-1:2020 [ECMAScript for PDF] are not)

[2] https://qpdf.sourceforge.io

[3] https://ghostscript.com/blog/pdfi.html

I know you're talking about GUI editing, but I've found libqpdf[1] incredibly useful for making programmatic PDF edits with minimal (typically no) structural disturbance.

[1] https://qpdf.sourceforge.io

Solved this. So the string which we were concerned about depends on the time, which is why it changes everytime a new document is generated with the same source PDF. it is a meaningless string really. from the documentation, it gives this explanatin. To be sure, i raised an issue with the guys at QPDF and they were quick to answer the question too. The explanation theyve given is even more clearer.

Hi, this is my first Emacs package! It provides a transient wrapper for the qpdf command-line tool aimed especially at users of pdf-tools or at least DocView. With it one can, for example, remove/reorder/split/rotate pages of a pdf file, merge pdf files, remove annotations, and apply a range of transformations to a pdf file. See the qpdf documentation.

There are some here, as test files in the qpdf library: https://github.com/qpdf/qpdf/tree/main/qpdf/qtest/qpdf

(I wrote a low-level PDF parser and ran it over the PDF files that happened to be present on my laptop—just regular ones—and ran into some files that (some) PDF viewers open but even qpdf doesn't. I say "even" because qpdf is really good IMO.)

If you're comfortable handling the (typo)graphical aspects of the PDF yourself and have the ability to consume a C++ library, I've had good experiences using the Apache-licensed qpdf[1] library to handle the low-level structural aspects of the PDF standard. It's particularly convenient when your application requires structure-preserving integration of existing PDF content.

Simple example applications, each completed in 2–3 days, both in C#, using C++/CLI to integrate libqpdf:

1. Overlaying fixed-format text on pre-existing blank PDF form pages, ensuring the content of each distinct form page is embedded exactly once, and that all necessary assets (fonts, images, etc.) from the blank form PDF pages are included in the output PDF.

2. Losslessly combining a sequence of PDF, TIFF, and JPEG images into a single PDF with bookmarks pointing to the first page of each source file and existing image compression maintained where possible. In this application, only the source TIFFs were anything other than arbitrary (i.e., the TIFFs were more-or-less baseline images coming from a small number of scanning systems, but the JPEGs and PDFs came from all sorts of different applications).

[1] https://github.com/qpdf/qpdf

Use qpdf https://github.com/qpdf/qpdf

I was looking for a way on macOS to batch remove the user password from a bunch of PDF files that had the same password. I found the easiest way was to use qpdf with the following command:

Homebrew is a highly popular package manager on macOS and Linux systems, enabling users to easily install, update, and uninstall command-line tools and applications. Its design philosophy focuses on simplifying the software installation process on macOS, eliminating the need for manual downloads and compilations of software packages.

Homebrew - package manager for linux-based OSs.

Package Manager: Homebrew

Hopping from one distro to another with a different package manager might require some time to adapt. Using a package manager that can be installed on most distro is one way to help you get to work faster. Flatpak is one of them; other alternative are Snap, Nix or Homebrew. Flatpak is a good starter, and if you have a bunch of free time, I suggest trying Nix.

Are you using SQLite that ships with macOS, or SQLite installed from homebrew?

I had a different problem in the past with the SQLite that ships with macOS, and have been using SQLite from homebrew since.

So if it’s the one that comes with macOS that gives you this problem that you are having, try using SQLite from homebrew instead.

https://brew.sh/

Before we begin, make sure you have Homebrew installed on your Mac. Homebrew is a package manager that makes it easy to install software and dependencies. You can install Homebrew by following the instructions on their website: https://brew.sh/

I’m on MacOS and erlang.org, elixir-lang.org, and postgresql.org all suggest installation via Homebrew, which is a very popular package manager for MacOS.

I have always either installed Node from the installer provided by the Nodejs website or, via Brew in macOS. I have also used nvm in the past but did not know that there was a best practice to guide us.

A running Rails application needs a database to connect to. You may already have your database of choice installed, but if not, I recommend PostgreSQL, or Postgres for short. On a Mac, probably the easiest way to install it is with Posrgres.app. Another option, the one I prefer, is to use Homebrew. With Homebrew installed, this command will install PostgreSQL version 16 along with libpq:

On a macOS machine, you can use homebrew by running the command.