The Lab Book Pages

An online collection of electronics information

Dr. Andrew Greensted
Last modified: 18th November 2009

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Writing papers can be made a real challenge when you have to fight with the software that help create them, especially when publishers require strange formats. Some of the bits below might help make things a little easier.

Setting PDF Metadata

Setting the metadata held in a PDF (author, title, subject etc..) is a nice extra touch. Here's one way of doing it.

If you want to start with what metadata is already present, you can use the line below to extract it to a file. If you want to start from scratch, then just skip this stage.

> pdftk myDocument.pdf data_dump output metadata

Now edit (or create) the metadata file to reflect what you want to change/set. Here is an example of a file.

InfoKey: Author
InfoValue: Your Name
InfoKey: Title
InfoValue: An Interesting Document Title
InfoKey: Subject
InfoValue: An equally interesting subject
InfoKey: Keywords
InfoValue: Stuff
InfoKey: Producer
InfoValue: Hand Crafted

Finally you need to merge your changes with your document. pdftk will only update the metadata held in your PDF with those mentioned in your metadata file. It leaves everything else untouched.

> pdftk myDocument.pdf update_info metadata output newDocument.pdf

Make pdflatex embed fonts

A few publishers require that all fonts are embedded in submitted publications. If you are using pdflatex, this is not the default. Fonts can be embedded quite simply by following the instructions below.

As root, run the updmap command.

> updmap --edit

Search for the following section in the file and change the pdftexDownloadBase14 option to true.

# pdftexDownloadBase14
# Should pdftex download the base 14 pdf fonts? Since some configurations
# (ps / pdf tools / printers) use bad default fonts, it is safer to download
# the fonts. The pdf files will get bigger, though.
# Valid settings are true (download the fonts) or false (don't download
# the fonts).
#pdftexDownloadBase14 false
pdftexDownloadBase14 true

Now rerun pdflatex on your document and check using pdffonts that the fonts are embedded.

> pdflatex myDoc.tex
> pdffonts myDoc.pdf
name                                 type         emb sub uni object ID
------------------------------------ ------------ --- --- --- ---------
ESWGSD+NimbusRomNo9L-Regu            Type 1       yes yes no       6  0
ICDSLR+NimbusRomNo9L-MediItal        Type 1       yes yes no       9  0
BOEROE+NimbusRomNo9L-Medi            Type 1       yes yes no      12  0
EMCVFH+NimbusRomNo9L-ReguItal        Type 1       yes yes no      15  0
IUDZBA+CMSY7                         Type 1       yes yes no      25  0
JWTDPY+NimbusMonL-Regu               Type 1       yes yes no      38  0
LSARCX+CMBX8                         Type 1       yes yes no      48  0
GZPYGD+CMBX6                         Type 1       yes yes no      51  0
FQUPLQ+CMR8                          Type 1       yes yes no      54  0
HPHQEW+CMMI8                         Type 1       yes yes no      57  0
GNNWKT+CMSY8                         Type 1       yes yes no      60  0
OSWSHQ+CMSY6                         Type 1       yes yes no      82  0

Paper Size During PS to PDF Conversion

Converting PS to PDF is very easy with the ps2pdf utility, but it doesn't always seem to respect the paper size of the original postscript file. This can be rectified with the command format below.

> ps2pdf -sPAPERSIZE=a4 doc.pdf

Stopping dvips Outputting Direct to Printer

When using dvips to convert your DVI into a postscript file, you can find your document suddenly being printed rather than going to a file. The reason is a configuration option in the dvips config file. Below is a snippet from the that will cause dvips to output the postscript to a file rather than sending it to lpr.

You just need to comment out the option that pipes o to lpr.

File Excerpt: /usr/share/texmf/dvips/config/
% How to print, maybe with lp instead lpr, etc. If commented-out, output
% will go into a file by default.
% o |lpr

Joining separate PDF files into a single 'Book'

There are a number of books available online for free. However, it's quite normal that the different book sections can only be downloaded separately. It makes life easier when printing and storing the book files if they can be joined in a single file. The method below uses pdflatex to do this. There are other ways, such as pdftk (described below), but this method is quite flexible.

The important part is the use of the pdfpages package, this allows you to include the PDF files. By also making use of the graphicx package it is possible to scale the included PDFs.

File: book.tex

% Set Page Size

% Support for PDF inclusion 

% Support for PDF scaling


% Globals: include all pages, don't auto scale

% Include the PDF files, scaling as required


After creating the tex file, use pdflatex to create the final single PDF.

> pdflatex book.tex

Using pdftk

An alternate approach is using the pdftk tool. The command below give an example of combining multiple PDFs into a single file.

> pdftk *.pdf cat output combined.pdf

It is a very flexible tool and does much more than this. The pdftk web site is well worth a look.

LaTeX Duplicate Labels Checker

LaTeX can be a little less than helpful when things go wrong. One such situation is when you have duplicate labels. The following command will search your .tex file for duplicated labels.

> grep -noE '\\label{.+}' document.tex | sed 's/:/ /' | uniq -D -f 1

It works as follows: grep is used to search for occurrences of \label{}. The -n flag turns on line number output. The output is piped through sed to convert the colon separator used by grep into a space. Finally, uniq searches for matching labels. The -f 1 flag makes uniq perform the unique test on the label field rather than the line number.

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