I can crop PDF (for example in Acrobat).
But text outside of the crop margin will still be maintained in the PDF (even though I don't see it in the viewable area).
I want to remove anything outside the crop margin. Is there a command line tool that can do so?
Ghostscript can do that. Ghostscript is a command line tool which is available for all major operating systems.
The command which does it for Linux or Mac OS X:
gs -o cropped-and-removed.pdf \
-sDEVICE=pdfwrite \
-dUseCropBox \
in.pdf
The command for Windows:
gswin64c.exe -o cropped.pdf ^
-sDEVICE=pdfwrite ^
-dUseCropBox ^
in.pdf
Be sure to use a rather recent version of Ghostscript. Current is v9.16.