Editing Installation (section)

==Testing and quick start==

Here are a few simple tests and a brief introduction to Madagascar:

Typing any Madagascar command in a terminal window without parameters should generate brief documentation. Try one of the following:

<pre>
sfin
sfattr
sfspike
sfbandpass
sfwiggle
</pre>

If you get an error like "Command not found," you may not have your <tt>&#36;PATH</tt> environment variable set correctly, or you may need to issue the <tt>rehash</tt> command.

Now try making a simple Madagascar data file:
<pre>
sfspike n1=1000 k1=300 > spike.rsf
</pre>

This command generates a one-dimensional list of 1000 numbers, all zero except for a spike equal to one at position 300. If this generates an error like
<pre>
Cannot write to data file /path/spike.rsf@: Bad file descriptor
</pre>
you may need to create the directory pointed to by your <tt>&#36;DATAPATH</tt> environment variable.

The file <tt>spike.rsf</tt> is a text header. The actual data are stored in the binary file pointed to by the <tt>in=</tt> parameter in the header.  You can look at the header file directly with <tt>more</tt>, or better, examine the file properties with
<pre>
sfin spike.rsf
</pre>

You can learn more about the contents of <tt>spike.rsf</tt> with
<pre>
sfattr < spike.rsf
</pre>

The following command applies a bandpass filter to <tt>spike.rsf</tt> and puts the result in <tt>filter.rsf</tt>:
<pre>
sfbandpass fhi=2 phase=y < spike.rsf > filter.rsf
</pre>

The following command makes a graphics file from <tt>filter.rsf</tt>:
<pre>
sfwiggle clip=0.02 title="Welcome to Madagascar" < filter.rsf > filter.vpl
</pre>

If you have an X11 display program running, and your <tt>&#36;DISPLAY</tt> environment variable is set correctly, you can display the graphics file with:

<pre>
sfpen < filter.vpl
</pre>

You can pipe Madagascar commands together and do the whole thing at once like this:

<pre>
sfspike n1=1000 k1=300 | sfbandpass fhi=2 phase=y | \
sfwiggle clip=0.02 title="Welcome to Madagascar" | sfpen
</pre>

If you have SCons installed, you can use it to automate Madagascar processing. Here is a simple <tt>SConstruct</tt> file to make <tt>filter.rsf</tt> and <tt>filter.vpl</tt>:

<syntaxhighlight lang="python">
#
# Setting up
#
from rsf.proj import *

#
# Make filter.rsf
#
Flow('filter',None,'spike n1=1000 k1=300 | bandpass fhi=2 phase=y')

#
# Make filter.vpl
#
Result('filter','wiggle clip=0.02 title="Welcome to Madagascar"')

End()
</syntaxhighlight>

Put the file in an empty directory, give it the name <tt>SConstruct</tt>, <tt>cd</tt> to that directory, and issue the command:

<pre>
scons
</pre>

The graphics file is now stored in the <tt>Fig</tt> subdirectory. You can view it manually with:

<pre>
sfpen Fig/filter.vpl
</pre>

... or you can use:

<pre>
scons view
</pre>

When a SConstruct file makes more than one graphics file, the  <tt>scons view</tt> command will display all of them in sequence. 
[[Image:filter.png|frame|center|Welcome to Madagascar.]]
Now edit the <tt>SConstruct</tt> file: change the title string on the <tt>Result</tt> line to "Hello World!", save the file, and rerun the scons command. You will see that scons has figured out that the file <tt>filter.rsf</tt> does not need to be rebuilt because nothing that affects it has changed. Only the file <tt>filter.vpl</tt> is rebuilt.