useful linux commands for pdf editor

pdfunite
       pdfunite merges several PDF (Portable Document Format) files in order of their occurrence on command line to one PDF result file.
EXAMPLE
       pdfunite sample1.pdf sample2.pdf sample.pdf
       merges all pages from sample1.pdf and sample2.pdf (in that order) and creates sample.pdf


pdftocairo
       pdftocairo [options] PDF-file [output-file]
DESCRIPTION
       pdftocairo  converts Portable Document Format (PDF) files, using the cairo output device of the pop‐pler PDF library, to any of the following output formats:
OPTIONS
       -png   Generates a PNG file(s)
       -jpeg  Generates a JPEG file(s)
       -tiff  Generates a TIFF file(s)
       -pdf   Generates a PDF file

pdfseparate
       pdfseparate extract single pages from a Portable Document Format (PDF).
       pdfseparate  reads  the  PDF  file PDF-file, extracts one or more pages, and writes one PDF file for each page to PDF-page-pattern, PDF-page-pattern should contain %d.  %d is replaced by the page  number.
EXAMPLE
       pdfseparate sample.pdf sample-%d.pdf
       extracts all pages from sample.pdf, if i.e. sample.pdf has 3 pages, it produces sample-1.pdf, sample-2.pdf, sample-3.pdf