Search directories and files with a grep utility

To demonstrate traversing and searching directory structures, we create a simple utility that works like Unix grep. This utility uses recursive_directory_iterator to traverse nested directories and searches files for matches with a regular expression.

How to do it…

In this recipe, we write a simple grep utility that traverses directories to search files with a regular expression:

• We start with some convenience aliases:

  namespace fs = std::filesystem;
  using de = fs::directory_entry;
  using rdit = fs::recursive_directory_iterator;
  using match_v = vector<std::pair<size_t, std::string>>;

match_v is a vector of regular expression match results.

• We continue using our formatter specialization for path objects:

  template<>
  struct std::formatter<fs::path>: std::formatter<std::string> {
      template<typename FormatContext>
      auto format...