Quickly Shrinking the File Size of a PDF File on the Command Line in Linux

Ok, I'm most linking to a great page here. But I'll also give you my favorite choice: GhostScript, which is available almost on every system and did a terrific job in my test:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

Of course it also takes other formats like ps and eps or jpg as input!