"pdfunite" is part of the "poppler-utils" package on Debian-based systems. (But older versions of poppler-utils don't include pdfunite, so the "gs" solution mi

"pdfunite" is part of the "poppler-utils" package on Debian-based systems. (But older versions of poppler-utils don't include pdfunite, so the "gs" solution might still be useful.)