Tadek’s Blog

For quite some time now I’ve been thinking of correlating tracklog GPS data from my GPS with the protos I’ve taken based on time. It looks such a thing alrady exists here and this blog contains a lot of good pointers.

I will try these out, but I still want something more automated… maybe I will write it one day…

As always with perl, there’s a couple of options

1. Automatically using CPAN perl -MCPAN -e shell install Perl::Module::You::Want

2. Automatically using g-cpan in Gentoo g-cpan -i Perl::Module::You::Want

3. Semi automatically in Debian

   • find a “lib-module-you-want-perl” module that provides the package you want.
   • command apt cache search “lib.*-perl” gives you a list of all prepackaged perl modules.
   • install “apt-get install”

4. By hand, described here.

Trying to automate something I had to run a program with a configuration file modified for each run. The easy way to do this is to create a template file and generate the correct configuration file with variable substitution for each run.

This task could be done in a number of ways (sed, perl, shell), to name a few, but as Diego pointed out there is already a tool for this m4. It’s a bit archaic and has odd syntax (think strange quotes or strangely named built-in macros), but it’s ideal for my simple task.

At the end I run it like this: m4 -Dparam1=value1 -Dparam2=value2 <infile> > <outfile>

As simple as that. Thanks Diego! BTW: some pointers to M4: manual and linux journal article.