It takes two PDF files as arguments. By default, its only output is its return code, which is 0 if there are no differences and 1 if the two PDFs differ. If given the `--output-diff` option, it produces a PDF file with visually highlighted differences. With the `--view` argument it opens a window that lets you view the files' pages and zoom in on details.

WWW: https://vslavik.github.io/diff-pdf
