Some useful PDF editing (and search) commands

  • Reduce PDF filesize: gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf Allowed PDFSETTINGS are /screen, /ebook, /printer, /prepress, /default. (from the ghostscript package)
  • Convert a color PDF into grayscale: gs -sOutputFile=output.pdf -sDEVICE=pdfwrite -sColorConversionStrategy=Gray -dProcessColorModel=/DeviceGray -dAutoRotatePages=/None -dCompatibilityLevel=1.4 -dNOPAUSE -dBATCH input.pdf (from the ghostscript package)

ps2pdf versus pstill and password protection of pdf documents

While reading about ps2pdf (which is just a commandline front-end to ghostscript), I realized that despite its simple appearance, ps2pdf has almost all capabilities of Acrobat 5. ps2pdf14 outputs Acrobat 5-compatible files. According to the documentation strong password protection should be possible, however, I never managed with that.

In theory the following commands should work:

-sOwnerPassword= and -sUserPassword=

In order to set the key length to 128 you have to use
ps2pdf14 -dEncryptionR=3 -dKeylength=128