How to Compress a PDF in Terminal

Open the terminal and go to the directory where the original PDF is located. For this example, let us say that the name of the PDF in question is called original.pdf.

Type in the command:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress -dNOPAUSE -dQUIET -dBATCH -sOutputFile=original_compressed.pdf original.pdf

And you should have the new file called original_compressed.pdf in the same directory!