Pdftk. Pdftk server is a command line tool that allows you to easily combine multiple pdf files into one. Pdftk is available after importing building of the clip which can take up to many or days depending on the computer of the excellent directories the speed of the lost drive user activity indexer nuisances and other factors.
It comes in three versions. Pdftk the pdf toolkit. Pdftk is a simple tool for doing everyday things with pdf documents you can merge pdf documents split pdf pages into a new document rotate pdf pages or documents decrypt input as necessary.
From the pdftk man page.
Pdftk server open source command line tool pdftk free and pdftk pro proprietary paid pdftk java is a port of pdftk into java. It comes in three versions. Pdftk builder is a free graphical interface to pdftk. Pdftk stands for pdf toolkit and pdftk server allows you to merge pdf documents split pdf pages into new documents rotate pdf pages decrypt and encrypt update metadata apply watermarks and much more.