void *p = malloc(n);
   if(!p && n != 0) {
     fprintf(stderr,
-            "selector: can not allocate memory: %s\n", strerror(errno));
+            "selector: cannot allocate memory: %s\n", strerror(errno));
     exit(EXIT_FAILURE);
   }
   return p;
   file = fopen(input_filename, "r");
 
   if(!file) {
-    fprintf(stderr, "selector: Can not open `%s'.\n", input_filename);
+    fprintf(stderr, "selector: Cannot open `%s'.\n", input_filename);
     exit(EXIT_FAILURE);
   }
 
         fprintf(out, "\n");
       } else {
         fprintf(stderr,
-                "selector: Can not open %s for writing.\n",
+                "selector: Cannot open %s for writing.\n",
                 output_filename);
         exit(EXIT_FAILURE);
       }