Installing PDFtk, ImageMagik, and PDFJam on Ubuntu 18.04

gistfile1.txt

##Pre 18.04 versions:
sudo apt-get install pdftk

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##Ubuntu 18.04 - #credit to abu_bua - see https://askubuntu.com/questions/1028522/how-can-i-install-pdftk-in-ubuntu-18-04-and-later

cd /tmp

wget http://launchpadlibrarian.net/340410966/libgcj17_6.4.0-8ubuntu1_amd64.deb \
 http://launchpadlibrarian.net/337429932/libgcj-common_6.4-3ubuntu1_all.deb \
 https://launchpad.net/ubuntu/+source/pdftk/2.02-4build1/+build/10581759/+files/pdftk_2.02-4build1_amd64.deb \
 https://launchpad.net/ubuntu/+source/pdftk/2.02-4build1/+build/10581759/+files/pdftk-dbg_2.02-4build1_amd64.deb

sudo apt-get install ./libgcj17_6.4.0-8ubuntu1_amd64.deb \
    ./libgcj-common_6.4-3ubuntu1_all.deb \
    ./pdftk_2.02-4build1_amd64.deb \
    ./pdftk-dbg_2.02-4build1_amd64.deb

rm ./libgcj17_6.4.0-8ubuntu1_amd64.deb
rm ./libgcj-common_6.4-3ubuntu1_all.deb
rm ./pdftk_2.02-4build1_amd64.deb
rm ./pdftk-dbg_2.02-4build1_amd64.deb

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##Installing ImageMagick
sudo apt-get install imagemagick

#you may get issues running convert, such as "not authorized `aaaa` @ error/constitute.c/ReadImage/453"
# credits to sNICkerssss - https://stackoverflow.com/questions/42928765/convertnot-authorized-aaaa-error-constitute-c-readimage-453/52715220

In file /etc/ImageMagick-6/policy.xml (or /etc/ImageMagick/policy.xml)

change line
<policy domain="coder" rights="none" pattern="PDF" />
to
<policy domain="coder" rights="read|write" pattern="PDF" />

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## Install PDFJam

sudo apt install texlive-extra-utils     (Needed for pdfjam)