Fix: Download pdftk_server-2.02-mac_osx-10.11-setup.pkg, not listed on the official website yet!
#!/bin/bash
VERSION='2.02'
PDFLABS='https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit'
PKG="pdftk_server-${VERSION}-mac_osx-10.06-setup"
CELLAR='/usr/local/Cellar/'
PDFTK=${CELLAR}/pdftk/${VERISON}
PWD=$(pwd)
cd /tmp
wget -o ${PKG}.pkg ${PDFLABS}/${PKG}.pkg
pkgutil --expand ${PKG}.pkg pdftk_package
cd pdftk_package
mv pdftk.pkg/Payload pdftk.pkg/payload.gz
gunzip pdftk.pkg/payload.gz
cpio -iv < pdftk.pkg/payload
mkdir -p ${PDFTK}/bin ${PDFTK}/lib ${PDFTK}/share/man/man1
mv bin/pdftk ${PDFTK}/bin/.
mv lib/* ${PDFTK}/lib/.
mv man/pdftk.1 ${PDFTK}/share/man/man1/.
cd $PWD
rm -rf /tmp/${PKG}.pkg /tmp/pdftk_package
brew doctor
brew link pdftk