Merge all pdf files from one folder

I have 250 pdf files in one folder that I want to merge in one document. The order does not matter. Is there a simple way of doing it?

I can use PDF-Shuffler as suggested here https://askubuntu.com/a/2805/247771 but the progam hangs for 10 minutes befor it has loaded all the pdfs.

Can I achive this maybe with an inline command like

pdftk *.pdf output mergedfiles.pdf

?

I would use pdfunite. It is nice and simple. cd to your directory. Then use something like this:

pdfunite *.pdf all.pdf

(Before running, make sure you don't already have a file called all.pdf in that directory.)

Thanks to steeldriver who showed me that this is doing the job:

pdftk *.pdf cat output mergedfiles.pdf

You can use qpdf as pdftk is not available in Ubuntu Bionic:

qpdf --empty --pages *.pdf -- out.pdf