byronc bits

Sparse Files and tar

GNU tar provides the -S option to efficiently handle sparse files. Of course it only works if you create the tarball with the -S option. That is all.

More Useful ViM Tags

Frequently, I find myself writing C code that requires the use of struct ifreq. There are plenty of fields there and of course there are other structures that I never remember. I could always look in the headers, but it ends up being a good amount of digging before I find the real definition and all its accompanying pieces. So, I decided to let ctags and ViM do the work for me. I created ~/bin/update_local_tags with the following contents:

#!/bin/sh
[ -d ~/.localtags ] || mkdir ~/.localtags
ctags -f ~/.localtags/usrinclude.ctags --exclude=vector\*.hpp -R /usr/include >/dev/null 2>&1

Then I created ~/.vim/ftplugin/c.vim with the following contents:

setlocal tags+=$HOME/.localtags/usrinclude.ctags

For good measure I copied c.vim to cpp.vim so it would be loaded for C++ file types also.

Now I just have to run update_local_tags to generate a tag file for everything in /usr/include and ViM automatically includes that list whenever I edit a C or C++ file. Updating the tags file is still a manual process, I should probably attempt to hook it into apt. Observant readers will have noticed that I exclude vector*.hpp when generating the tags. Boost includes a few generated header files that match this pattern and swell the tag file to almost 750 MiB.

application/vnd.fdf and pdftk

So, if a webserver ever serves you a fdf file, you can view the resulting form with evince or your favorite pdf viewer. Just check the beginning of the fdf file to see which form the fields should be applied to and then run

pdftk form.pdf fill_form my.fdf output filledform.pdf

Mercurial Presentation

I'm presenting on Mercurial at the Utah Python Users Group tonight. Probably not as useful without the demos, but here are my slides: mercurial.pdf. Sadly, the slides really just seem to be my notes on a pretty background.

Using the verbatim Environment and listings Package with Beamer

I finally figured out how to make the verbatim environment work with Beamer. Beamer can't handle the following code:

\begin{frame}{A Title}
    \begin{verbatim}
    Don't mess with my text.
    \end{verbatim}
\end{frame}

To make it work, you need to include the fragile option for the frame. Example:

\begin{frame}[fragile]{A Title}
    \begin{verbatim}
    Don't mess with my text.
    \end{verbatim}
\end{frame}

If you use the listings package, the same trick works for the lstlistings environment.