diff --git a/rendu/semaphore_basics.c b/rendu/semaphore_basics.c
new file mode 100644
index 0000000..768cc4c
--- /dev/null
+++ b/rendu/semaphore_basics.c
@@ -0,0 +1,95 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   semaphore_basics.c                                 :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: ruiferna <ruiferna@student.42porto.com>    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/10/14 18:59:45 by ruiferna          #+#    #+#             */
+/*   Updated: 2025/10/14 20:34:46 by ruiferna         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <semaphore.h>
+#include <fcntl.h>
+
+#define NUM_CHILDREN 5
+#define NUM_RESOURCES 3
+#define SEM_NAME "/philo_sem"
+
+int main(int argc, char *argv[]) {
+    sem_t *sem;
+    pid_t pids[NUM_CHILDREN];
+    int i;
+
+	(void) argc;
+	(void) argv;
+    // Remove semaphore if it exists from previous run
+    sem_unlink(SEM_NAME);
+
+    // Create semaphore with 3 resources
+    sem = sem_open(SEM_NAME, O_CREAT | O_EXCL, 0644, NUM_RESOURCES);
+    if (sem == SEM_FAILED) {
+        printf("Error creating semaphore\n");
+        return 1;
+    }
+	
+	i = 0;
+    while (i < NUM_CHILDREN)
+	{
+        pids[i] = fork();
+        if (pids[i] == -1) {
+            printf("Error creating process\n");
+            return 1;
+        }
+        if (pids[i] == 0) {
+            // Child process
+            int child_id = i + 1;
+            sem_t *child_sem;
+
+            // Open semaphore in child process
+            child_sem = sem_open(SEM_NAME, 0);
+            if (child_sem == SEM_FAILED) {
+                printf("Child %d: Error opening semaphore\n", child_id);
+                exit(1);
+            }
+
+            printf("Child %d (PID: %d): Waiting for resource...\n", child_id, getpid());
+            
+            // Acquire resource
+            sem_wait(child_sem);
+            printf("Child %d (PID: %d): Acquired resource\n", child_id, getpid());
+            
+            // Use resource for 500ms
+            printf("Child %d (PID: %d): Using resource...\n", child_id, getpid());
+            usleep(500000);
+            
+            // Release resource
+            printf("Child %d (PID: %d): Released resource\n", child_id, getpid());
+            sem_post(child_sem);
+
+            sem_close(child_sem);
+            exit(0);
+        }
+		i++;
+    }
+
+    // Use waitpid() to wait for all children to finish
+	i = 0;
+    while (i < NUM_CHILDREN)
+	{
+        waitpid(pids[i], NULL, 0);
+		i++;
+    }
+
+    // Clean semaphone
+    sem_close(sem);
+    sem_unlink(SEM_NAME);
+
+    return (0);
+}
+
diff --git a/testers/test_13_semaphore_basics.sh b/testers/test_13_semaphore_basics.sh
index b5d7c0d..df0a922 100755
--- a/testers/test_13_semaphore_basics.sh
+++ b/testers/test_13_semaphore_basics.sh
@@ -133,7 +133,7 @@ echo -n "Test 6: No zombie processes... "
 "$EXE_PATH" > /dev/null 2>&1 &
 PARENT_PID=$!
 sleep 1
-ZOMBIE_COUNT=$(ps aux | grep "$PARENT_PID" | grep -c "defunct" || echo "0")
+ZOMBIE_COUNT=$(ps aux | grep "$PARENT_PID" | grep "defunct" | wc -l)
 wait $PARENT_PID 2>/dev/null
 if [ "$ZOMBIE_COUNT" -eq 0 ]; then
     echo -e "${GREEN}✓ PASSED${NC}"