Tools
Command examples
Combines different pdf in one (Pdftk)
Fixed list the order of input file is important, combine 1.pdf, 2.pdf and 3.pdf in 123.pdf
$ pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf
All the pdf of the directory by alphabetic order in all.pdf file:
$ pdftk *.pdf cat output all.pdf
Puts several page on one sheet (PDFjam)
Two page per sheet on top of each other
$ pdfnup --nup 1x2 input.pdf
Two page per sheet on side by side
$ pdfnup --nup 2x1 input.pdf