pdfjamコマンドを使う
http://www2.warwick.ac.uk/fac/sci/statistics/staff/academic-research/firth/software/pdfjam/
pdfjam main.pdf --landscape --nup 2x1 -o output2x1.pdf
pdfjamコマンドを使う
http://www2.warwick.ac.uk/fac/sci/statistics/staff/academic-research/firth/software/pdfjam/
pdfjam main.pdf --landscape --nup 2x1 -o output2x1.pdf