What freeware is there to batch process PDF via command line?

Question

Command line

Good afternoon, you need free software that allows you to batch process a large number of PDF files
Namely, there is a network folder where various documents, letters, etc. are scanned.
But everyone has their own scanning settings, and it turns out that someone can scan in color, someone in very good quality, as a result of which the file begins to weigh a large number of megabytes, etc. etc.
You need such software that could be called from a bat-nickname, and it would compress the files to the set settings, for example, everything in grayscale, 300 dpi, such and such a compression quality

Answer 1

Hello
qpdf.sourceforge.net