diff --git a/c-programming/io/freadln.c b/c-programming/io/freadln.c
index 1498812..ea8840c 100644
--- a/c-programming/io/freadln.c
+++ b/c-programming/io/freadln.c
@@ -81,7 +81,9 @@ int freadln(FILE* f, char** output, size_t* length_out) {
 }
 
 #ifdef TEST
+# include <ctype.h>
 # include <inttypes.h>
+# include <stdbool.h>
 # include <stdint.h>
 
 # if POSIX
@@ -124,6 +126,15 @@ typedef size_t SIZE_T_FORMAT;
 
 # define YN(boolean) ((boolean) ? "yes" : "no")
 
+bool file_exists(const char* path);
+
+bool file_exists(const char* path) {
+	FILE* f = fopen(path, "rb");
+	return !((f == NULL
+	       /* close file if it was successfully opened */ || (fclose(f), false))
+	         && errno == ENOENT);
+}
+
 int main(void) {
 	// stdin test
 	printf("Type something> ");
@@ -136,6 +147,21 @@ int main(void) {
 
 	// file test
 #define TEST_FILE "freadln_test.txt"
+	if (file_exists(TEST_FILE)) {
+		fflush(stdout);
+		fprintf(stderr, "Error: A file `" TEST_FILE "` exists. Are you sure "
+		        "you want to continue and\noverwrite it? [[y = Enter]/n]: ");
+		fflush(stderr);
+		size_t line_length;
+		if (finreadln(&line, &line_length) == freadln_ERROR) {
+			perror("freadln");
+			return EXIT_FAILURE;
+		} else if (line_length >= 1) {
+			if (tolower(line[0]) == 'n')
+				return EXIT_FAILURE;
+		}
+	}
+
 	FILE* f = fopen(TEST_FILE, "w");
 	if (f == NULL) {
 		perror("fopen");