====== qpdf ======
  * http://qpdf.sourceforge.net/
  * https://github.com/qpdf/qpdf
  * PDF 명령행 편집도구

===== 여러 PDF 합치기 =====
[[https://stackoverflow.com/questions/2507766/merge-convert-multiple-pdf-files-into-one-pdf|linux - Merge / convert multiple PDF files into one PDF - Stack Overflow]]

<code>
# 특정 파일지정
qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf

# 여러개 전부다
qpdf --empty --pages *.pdf -- out.pdf

</code>