else if(strcmp(argv[i], "-f") == 0) {
check_opt(argc, argv, i, 1, "<input filename>");
strncpy(input_filename, argv[i+1], buffer_size);
else if(strcmp(argv[i], "-f") == 0) {
check_opt(argc, argv, i, 1, "<input filename>");
strncpy(input_filename, argv[i+1], buffer_size);
<< " -e start in regexp mode" << endl
<< " -a case sensitive" << endl
<< " -m monochrome mode" << endl
<< " -e start in regexp mode" << endl
<< " -a case sensitive" << endl
<< " -m monochrome mode" << endl