The command-line tools are provided by sumatrapdf-tool, which is installed next to SumatraPDF.exe. They only work after SumatraPDF has been installed.
Available in pre-release 3.7
Usage: sumatrapdf-tool poster [options] input.pdf [output.pdf]
poster splits large PDF pages into many tiles.
Imagine you want to print PDF page in a larger size. poster allows you to create a PDF where each PDF page is enlarged and split into multiple pages, you can print separately and then stitch together.
To print a page that is twice as big in both x and y dimensions:
sumatrapdf-tool poster -x 2 -y 2 input.pdf output.pdf
-x and -y are the number of pieces to divide each page into horizontally and vertically, so -x 2 -y 2 turns every PDF page into 4 pages you can print separately and assemble into a bigger print.
Use -m to add an overlap (in points or as a percentage) between adjacent tiles, which makes it easier to align and glue them together. If you don’t specify an output file, it writes to out.pdf.

All options #

Usage: SumatraPDF poster [options] input.pdf [output.pdf]
  -p -    password
  -m -    margin (overlap) between pages (pts, or %)
  -x      x decimation factor
  -y      y decimation factor
  -r      split right-to-left