Open a PDF with an initial zoom level, specified as DPI, of 72

MuPDF is a lightweight PDF, XPS, and E-book viewer.
More information: <https://www.mupdf.com>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

mupdf -r {{72}} {{filename}}

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