Concatenate two PDFs

Convert PDF files, query information and extract data.
More information: <https://mupdf.com/docs>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

mutool merge -o {{output.pdf}} {{input1.pdf}} {{input2.pdf}}

click the source code to copy install mutool on any operating system with command-not-found.com