Here is a handy and useful Linux and Unix shell script that reduce PDF file size using Ghostscript. No need to upload your PDF file to the shady third-party website. Just do it from the terminal. I tested it with both CentOS and Ubuntu/Debian Linux.
from [RSS/Feed] nixCraft: Linux Tips, Hacks, Tutorials, And Ideas In Blog Format https://bash.cyberciti.biz/file-management/linux-shell-script-to-reduce-pdf-file-size/