====== How to merge PDF-files ======

===== Introduction =====

PDF (Portable Document Format) is a file format invented by Adobe. PDF is useful to present documents independent of hardware, operating system and application software. Each PDF file has a fixed layout, including page size, fonts, graphics and other information. It is also possible to encrypt a PDF file for security, or create a digital signature for authentication.

<note important>Work in Progress!!!</note>

PDF documents are created from traditional text documents via a printer driver, or as with LaTeX, created directly from source-code. One important consequence is that one cannot convert a PDF-document "back" into it's original format such as a Microsoft Word document.

This article describes how you can merge several PDF documents into a single PDF document. For example, this is useful if you have several pages from a scanner in PDF format and want to put these files into one file. There are several tools available; some are included in the stock Slackware install as well as others that can be readily installed.

===== Default Tools =====

Tools which are already available on your Slackware computer if you have a complete installation.

==== imagemagick (convert) ====

The convert tool comes in Slackware's imagemagick package from the xap-series.

The convert tool uses the -adjoin option to achieve this.
<code>convert -adjoin file1.pdf file2.pdf merged.pdf</code>
Thanks to jlinkels for the contribution.

To increase the quality of the output, it is better to read the input PDF files with a higher density (in dots per inch (DPI)) and then resize the output density back to common DPI, 96 for example. I usually use an input density of 600 (after many trial and errors), and then resize with 93.75% (if you dont resize you will get a huge output file).
<code>convert -density 600 fileinput_1.pdf fileinput2_.pdf -resize 93.75% output.pdf</code>
Thanks to eXpander_ for the contribution.

==== ghostscript (gs) ====

The ghostscript package resides in Slackware's ap-series.

With GhostScript you can merge PDF files on the command line.
<code>gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=<newfilename>.pdf <inputfilenameshere></code>
Thanks to mrclisdue for the contribution.

==== pdfconcat ====

The pdfconcat tool comes in Slackware's xpaint package from the xap-series.

<code>pdfconcat -o <output.pdf> <input1.pdf> [...]</code>
Thanks to BroX for the contribution.

==== pdfunite ====

The pdfunite tool comes in Slackware's poppler package from the l-series.

<code>pdfunite [options] PDF-sourcefile1..PDF-sourcefilen PDF-destfile</code>
Thanks to nivieru for the contribution.

===== Additional tools =====

Additional tools that can be easily installed.

==== pdftk ====

pdftk is available at [[http://slackbuilds.org/repository/14.0/office/pdftk/|slackbuilds.org]]. It is also a command line tool and the usage is:
<code>pdftk first.pdf second.pdf third.pdf cat output altogether.pdf</code>
pdftk can do more things than joining PDF files, for example rotating a document by 180 degrees is done this way:
<code>pdftk upsidedown.pdf cat 1-endsouth output rotated.pdf</code>
Thanks to brianL and michaelk for pointing me to pdftk.

==== pdfshuffler ====

pdfshuffler is also available at [[http://slackbuilds.org/repository/14.0/office/pdfshuffler/|slackbuilds.org]]. It comes with a graphical user interface and is written in Python, therefore [[http://slackbuilds.org/repository/14.0/python/pyPdf/|pyPdf]] and [[http://slackbuilds.org/repository/14.0/python/pypoppler/|pypoppler]] are required in order to get this program to work. It is very convenient because it comes with a document-viewer and shows what you're doing. It has additional features like rotating or splitting PDF files.

==== pdfjam ====

pdfjam is a LaTeX-package which is unfortunately **not** included in tetex. But those of us who have installed texlive instead already have pdfjam. It is also a command line tool (like LaTeX). The documentation is available with the texdoc command
<code>texdoc pdfjam</code>
Thanks to joghi for pointing me to pdfjam.

<note>TODO: handling bookmarks in PDF-files, which of the above tools can handle those bookmarks?</note>

====== Sources ======
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  * Originally written by [[wiki:user:markush | Markus Hutmacher]] 
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http://www.linuxquestions.org/questions/slackware-14/which-tool-for-merging-pdf-files-4175453632/
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