- strcpy(name, sequence[z].filename);
- name[p - sequence[z].filename] = '\0';
- strcat(name, "colorized_");
+ if (output_prefix[0] == '\0') {
+ strcpy(name, sequence[z].filename);
+ name[p - sequence[z].filename] = '\0';
+ strcat(name, "colorized_");
+ } else {
+ strcpy(name, output_prefix);
+ }