+/**
+ * para_filter's main function.
+ *
+ * para_filter reads data from stdin, converts it by using a chain
+ * of filters (specified on the command line) and writes the resulting
+ * data to stdout.
+ *
+ * \param argc number of command line options
+ * \param argv vector of arguments
+ *
+ * \return \a EXIT_SUCCESS on success, EXIT_FAILURE on errors.
+ */