JMM’s notes on

PDFs (Portable Document Format)

Command Line

Some common tasks I do with PDFs.

Selecting a range of pages

If you want to make a new PDF that only has some pages, this is how to do it with pdftk: 

pdftk input.pdf cat 1-4 8 output out.pdf

This takes in an input.pdf, takes pages 1 through 4 and page 8 and makes a 5-page output called output.pdf.

Concatenating PDFs

pdftk is also useful for concatenating PDFs: 

pdftk input1.pdf input2.pdf cat output out.pdf

You can also use the following format to select specific pages: 

pdftk A=input1.pdf B=input2.pdf cat A1 B1 A1 B1 output out.pdf

This makes a four page PDF. This is sometimes useful when I want to print junior-sized PDFs on letter paper.

SVG to PDF

This is covered in my Inkscape notes, but repeated here: 

inkscape --export-type=pdf --export-filename=output.pdf input.svg

Word Doc to PDF

unoconv -T 30 -f pdf input.docx

Here, -T 30 makes a 30 second timeout. This is just a workaround for me, since otherwise the first time I try to launch unoconv it’ll typically time out as it takes a while to start up a server (I think that’s what’s going on).

Setting metadata

You can use this to set the title of a PDF. I didn’t like the default title that Xournal++ set, so I wanted to overwrite it. 

exiftool -Title="Some Title" -Author="Jane Whoever" -xmptitle= something.pdf

This is adapted from this askubuntu.com answer. Note that previous PDF metadata is still recoverable. You can reverse an update using: 

exiftool -PDF-update:all= something.pdf

If you linearize the PDF, though, this is no longer reversible. You can do this with: 

qpdf --linearize in.pdf out.pdf

There are other issues to consider with PDF metadata. Julien Voisin has an article about PDF metadata if you’re concerned about leaking information. He suggests using mat2. Which you can use like so: 

mat2 ./something.pdf

This’ll create a file called “something.cleaned.pdf”. It’ll likely be a much larger file size as text is converted to paths (at least, it seems this way since text no longer becomes selectable).

Rotate PDF

Here’s how to rotate a PDF 90° clockwise. 

qpdf in.pdf out.pdf --rotate=+90

PDF booklets

I print out half-sized (or “junior”-sized) PDFs (like A5 vs A4) often. See junior-pdf.nix for a script that does this. It basically makes it easy to print a PDF that can be cut and bound easily.

Tools