Combine multiple PDF documents into one

Just a quick one, as I now needed this for the second time and already didn't write it down the first time …
I found this when looking for a way to combine multiple PDF documents into one. You just need to

• sudo apt-get install gs pdftk


• gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=combinedpdf.pdf -dBATCH 1.pdf 2.pdf 3.pdf

Pretty self explaining, so I'm gonna end early here.

Unable to open PDFs in KPDF

After installing the latest Adobe Reader directly from Adobe's site (I quickly uninstalled the version from Medibuntu again that I blogged about before, because I couldn't choose a german locale), I noticed I couldn't open my PDFs in KPDF anymore. I found some errors from AppArmor in /etc/messages, but according to Google they were not relevant. Than I found a post describing the same behaviour, noting that starting KPDF as root worked. I checked it, same with me.

When starting KPDF from the commandline, a warning is shown:

kpdf: WARNING: Unknown mimetype 'application/x-kdeuser1'.

This hints at the solution: Adobe Reader installation obviously messed up mime types, going to Konqueror -> Settings -> Configure Konqueror -> File Associations -> Known Types -> applications and deleting user x-kdeuser1 (I also had x-kdeuser2) solved the problem.