Why not parse `ls` and what to do instead(unix.stackexchange.com)

  find . -maxdepth 1 -name "*.jpg" -print0 |\
  xargs -0P $(nproc --all) -I,, gm convert resize '200x200^>' -quality 75 ,, "thumbnails/,,"

  for i in *.jpg; resize 200x200 "$i" "thumbnails/$i"; end

  for name in subdir/subsubdir/*; do
    echo "${name#subdir/}"  # subsubdir/foo
  done

  cd some/dir/here
  find . -name '*.gz'
  cd - # changes back to previous directory

  find . -name '*.hs' -exec basename {} \;

  for f in subdir/*; do
    ...
  done

  ( 
  cd subdir || exit 1
  for f in *; do
    ...
  done
  )

    #define _GNU_SOURCE
    #include <dirent.h>
    #include <fcntl.h>
    #include <malloc.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>

    #define BUF_SIZE 32768

    struct linux_dirent64 {
      ino64_t d_ino;           /* 64-bit inode number */
      off64_t d_off;           /* Not an offset; see getdents() */
      unsigned short d_reclen; /* Size of this dirent */
      unsigned char d_type;    /* File type */
      char d_name[];           /* Filename (null-terminated) */
    };

    int writeall(char *buf, size_t len) {
      ssize_t wres = 0;
      wres = write(1, buf, len);
      if (wres == -1) {
        perror("write");
        return -1;
      }
      if (((size_t)wres) < len) {
        return writeall(buf + wres, len - wres);
      }
      return 0;
    }

    int main(int argc, char **argv) {
      if (argc != 2) {
        return EXIT_FAILURE;
      }
      int fd = open(argv[1], O_DIRECTORY | O_RDONLY);
      if (fd == -1) {
        perror("open");
        return EXIT_FAILURE;
      }
      void *buf = malloc(BUF_SIZE);
      ssize_t res = 0;
      do {
        res = getdents64(fd, buf, BUF_SIZE);
        if (res == -1) {
          perror("getdents64");
          return EXIT_FAILURE;
        }
        void *it = buf;
        while (it < (buf + res)) {
          struct linux_dirent64 *elem = it;
          it += elem->d_reclen;
          size_t len = strlen(elem->d_name);
          if (writeall(elem->d_name, len + 1) == -1) {
            return EXIT_FAILURE;
          }
        }
      } while (res > 0);
      return EXIT_SUCCESS;
    }