Lab 14: File comparison

One of the important uses of the VILLASnode toolbox is the comparison of a list of files.

The following command can be used to compare the files:

$ villas-test-cmp [OPTIONS] FILE1 FILE2 ... FILEn

where options refers to one or more of the following:

Option	Description
-d LVL	Adjust the debug level
-e EPS	Set epsilon for floating point comparisons to EPS
-v	Ignore data values
-T	Ignore timestamp
-s	Ignore sequence no
-F fmt	File format for all files
-t DT	The data-type format string
-h	show this usage information
-V	show the version of the tool

In this example we shall use this tool to compare two files. In the first terminal execute the following command:

$ villas signal sine > file_send.dat
$ villas pipe lab3.conf villas_node1 < file_send.dat

Open a second terminal to record the data being sent into another file. Execute the following command:

$ villas pipe -x lab3.conf villas_node1 > file_receive.dat

Now run the following command to compare the two files. He we ignore the timestamps since it will be different in both the cases:

$ villas test-cmp -T file_send.dat file_receive.dat

Following return codes are obtained based on the similarity between the two files:

Return codes:
  0   files are equal
  1   file length not equal
  2   sequence no not equal
  3   timestamp not equal
  4   number of values is not equal
  5   data is not equal

Following command can be used to determine the return codes:

echo $?

Since the files are equal in this example we get 0 as the return code.

Go to [lab 16] =>(node-lab-15)