code, which is 0 if there are no differences and 1 if the two PDFs differ. If
--output-diff option, it produces a PDF file with visually
$ diff-pdf --output-diff=diff.pdf a.pdf b.pdf
Another option is to compare the two files visually in a simple GUI, using
$ diff-pdf --view a.pdf b.pdf
This opens a window that lets you view the files' pages and zoom in on details.
It is also possible to shift the two pages relatively to each other using
Ctrl-arrows (Cmd-arrows on MacOS). This is useful for identifying translation-only differences.
See the output of
$ diff-pdf --help for complete list of options.