A little C program (script!) that checks if the braces are closed on stdin.

closedbraces.c

#include <stdio.h>
   
int main(void)
{
  FILE *fp;
  fp = stdin;
  
  int depth = 0;
  int c;
  
  while (!feof(fp)) {
    c = fgetc(fp);
    
    if (c == '{') {
      depth++;
    } else if (c == '}') {
      depth--;
    }
  }

  if (depth == 0) {
    printf("All braces have been closed!\n");
  } else if (depth > 1) {
    printf("Some braces have been left open! (%c)\n", depth);
  }
  
  return 0;
}