.. default-role:: literal


PDF tips and tricks
===================

Tips and tricks when working with the PDF_ file format

.. _PDF: http://en.wikipedia.org/wiki/PDF

Decrypting a file
-----------------

When your PDF file is password-protected, you can use xpdf_ to open it. Still it
will not save it without the password which is annoying.

To do this, the solution I have found is to convert the file to postscript_ and
then back to pdf. Note however that you may loose some information in the
process.

You will need poppler_ (for `pdftops`) and ghostscript_ (`ps2pdf`) for this to
work. Assume you want to decrypt the file `secret.pdf` which has the password
`foobar`, then run::

    $ pdftops -opw foobar secret.pdf
    $ ps2pdf secret.ps && rm secret.ps

.. _xpdf: http://www.foolabs.com/xpdf/
.. _postscript: http://en.wikipedia.org/wiki/PostScript
.. _poppler: http://poppler.freedesktop.org/
.. _ghostscript: http://pages.cs.wisc.edu/~ghost/

Merging several files
---------------------

To concatenate several files into just one, just run::

    $ gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=out.pdf -dBATCH $file1 $file2 ...

Where `gs` is provided by ghostscript_.

.. _ghostscript: http://pages.cs.wisc.edu/~ghost/

Extracting only some pages
--------------------------

To extract only from page `$start` to page `$end`, of your document `$input`,
and create a new pdf `$output` with those pages, run::

    $ gs -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -dSAFER \
         -dFirstPage=$start -dLastPage=$end \
	 -sOutputFile=$output $input

My source for this trick is `this tech tip article from Linux Journal`_.

.. _this tech tip article from Linux Journal: http://www.linuxjournal.com/content/tech-tip-extract-pages-pdf