Added README files

README.md

@@ -8,6 +8,7 @@ Welcome! This is a collection of chapter summaries from the book **Linux System
 - [Chapter 2 – File I/O](chp2/README.md)
 - [Chapter 3 – Buffered I/O](chp3/README.md)
 - [Chapter 4 – Advanced File I/O](chp4/README.md)
+- [Chapter 5 - Process Management](chp5/README.md)
 
 > Each file contains an English summary of the chapter's key concepts.
 

chp5/README.md

@@ -0,0 +1,73 @@
+# 📘 Chapter 5 – Process Management (Summary)
+**Based on _Linux System Programming_ by Robert Love**
+
+This chapter covers how Linux manages processes, including their creation, execution, and termination. It introduces key system calls and concepts that underpin multitasking and process control in Unix-like systems.
+
+---
+
+## 🧠 Core Concepts
+- A **process** is an independent program with its own memory and execution context.
+- The kernel provides **process abstraction** to manage concurrency.
+- Processes are scheduled and isolated using virtual memory and process control blocks (PCBs).
+
+---
+
+## 🛠️ Process Creation & Termination
+- `fork()` creates a new process (child) by duplicating the calling (parent) process using **copy-on-write**.
+- `exec()` replaces the current process image with a new program.
+- `wait()` and `waitpid()` allow the parent to wait for and collect the child’s exit status.
+- `exit()` performs cleanup and exits the process gracefully.
+- `_exit()` exits immediately without flushing stdio buffers.
+
+---
+
+## 🔍 Signals & Zombies
+- **Zombie processes** occur when a child exits but the parent doesn’t read its status with `wait()`.
+- `SIGCHLD` is sent to the parent when a child terminates.
+- The `init` process (PID 1) will adopt and clean up orphaned children.
+
+---
+
+## 👥 Process Hierarchies
+- Every process has a unique **PID** and a **PPID** (parent PID).
+- Together they form a **process tree**, starting from `init`.
+- Tools like `ps`, `pstree`, and `/proc` are useful for visualizing process hierarchies.
+
+---
+
+## 🎯 Process Identifiers & Groups
+- `getpid()` returns the process’s ID.
+- `getppid()` returns the parent’s ID.
+- **Process groups** and **sessions** enable job control, allowing signals to be sent to multiple related processes.
+
+---
+
+## 🧩 Resource Cleanup
+- On termination, the kernel reclaims:
+  - Memory
+  - Open file descriptors
+  - IPC resources
+- `exit()` also triggers:
+  - `atexit()` handlers
+  - Standard I/O flushes
+  - Potential creation of core dumps (if enabled)
+
+---
+
+## ✅ Why This Matters
+A strong understanding of process control is essential for:
+- Writing daemons
+- Managing background jobs
+- Building shells or supervisors
+- Avoiding resource leaks and zombie processes
+
+---
+
+## 📚 References
+- _Linux System Programming_, 2nd Edition by Robert Love (O'Reilly)
+- `man 2 fork`, `man 2 execve`, `man 2 wait`, `man 2 exit`, `man 7 signal`
+
+---
+
+*This summary is for educational purposes.*
+