Merge pdf files with numerical sort

Question

I am trying to write a bash script to merge all pdf files of a directory into one single pdf file. The command pdfunite *.pdf output.pdf successfully achieves this

Answer 1

Do it in multiple steps. I am assuming you have files from 1 to 99.

 pdfunite $(find ./ -regex ".*[^0-9][0-9][^0-9].*"  | sort) out1.pdf
 pdfunite out1.pdf $(find ./ -regex ".*[^0-9]1[0-9][^0-9].*"  | sort) out2.pdf
 pdfunite out2.pdf $(find ./ -regex ".*[^0-9]2[0-9][^0-9].*"  | sort) out3.pdf

and so on.

the final file will consist of all your pdfs in numerical order.

!!! Beware of writing the output file such as out1.pdf etc. otherwise pdfunite will overwrite the last file !!!

Edit: Sorry I was missing the [^0-9] in each regex. Corrected it in the above commands.