shrink.sh

gs                              \
      -q -dNOPAUSE -dBATCH -dSAFER          \
      -sDEVICE=pdfwrite                     \
      -dNumRenderingThreads=2               \
      -dEmbedAllFonts=true                  \
      -dSubsetFonts=true                    \
      -dDownsampleColorImages=true          \
      -dColorImageDownsampleType=/Bicubic   \
      -dColorImageResolution=72             \
      -dDownsampleGrayImages=true           \
      -dGrayImageDownsampleType=/Bicubic    \
      -dGrayImageResolution=72              \
      -dDownsampleMonoImages=true           \
      -dMonoImageDownsampleType=/Bicubic    \
      -dMonoImageResolution=72              \
      -sOutputFile='out.pdf'        \
      'in.pdf'