public void addOnlyInstrumentReg(String arg) {
        String patternString = arg.substring(ONLY_INSTRUMENT_REG_PREFIX.length());
        if (patternString.startsWith("/"))
            patternString = patternString.substring(1);
        defaultSkip = true;
        try {
            patternMatchers.add(PatternMatcherRegEx.getIncludePatternMatcher(patternString));
        } catch (PatternSyntaxException e) {
            setInvalid(format("Invalid pattern '%s'", patternString));
            e.printStackTrace(System.err);
        }
    }