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Using programs

Madagascar programs follow the standard UNIX conventions for reading and writing RSF files to and from stdin and stdout. This is also the convention that Seismic Unix uses, so it should be familiar to SU users. For example: the program sfattr allows us to get attributes about an RSF file (mean, standard deviation, min, max, etc.) To get the attributes for a pre-computed file, we might use

sfattr < file.rsf
     rms =       1.41316 
   mean =      0.999667 
 2-norm =       357.503 
 variance =      0.997693 
std dev =      0.998846 
    max =       5.05567 at 36 8 27 
    min =      -3.59936 at 18 9 6 
 nonzero samples = 64000 
 total samples = 64000

We demonstrate how to read and write RSF files using sfwindow which is a program that allows us to select portions of an RSF file. When sfwindow is used without any additional parameters, we are able to make a copy of a file with a different filename. For example:

 sfwindow < file.rsf > file2.rsf

gives us two files, file.rsf and file2.rsf which are identical but not the same file. If your intention is simply to copy a file, you can also use sfcp. In addition to specifying files to read in and out on the command line we can specify the parameters for each program that are necessary for it to run, or to produce the desired result. The general format for specifying parameters on the command line is key=val, where key is the name of the parameter that you want to set, and val is the value of the parameter. There are four (4) types of values that are acceptable: integers, floating point numbers, booleans, or strings. Going back to the window program, we can specify the number of traces or pieces of the file that we want to keep like:

sfwindow < file.rsf n1=10 > file-win.rsf

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