Merge PDFs with the command line

1. Install Ghostscript and pdftk.
   sudo aptitude install ghostscript pdftk -y
2. Put this script in ~/bin.
   http://einrad.eu/stuff/pdfmerge
3. Make it executable.
   chmod +x ~/bin/pdfmerge
4. Log out. Log in.
5. Use it.
   pdfmerge output.pdf a.pdf b.pdf c.pdf