Glue/combine mutiple pdf pages into one single page

From https://superuser.com/questions/366490/how-to-merge-multiple-pdf-files-onto-one-page-with-pdftk

Ole Tange's answer:

pdfjam Page1.pdf Page2.pdf --nup 2x1 --landscape --outfile Page1+2.pdf

It puts 2 pages on one page horizontally (1 row, two columns).
 

 

If you wanted to glue pages vertically, use --nup 1x2 --no-landscape

 

If you wanted no auto-scaling of pages (mine stretches output to fill a4 by default), use --noautoscale true