Linux Process Monitor

A lightweight Linux Process Monitor written in C that demonstrates how modern operating systems expose process information through the /proc virtual filesystem.

The project reads process metadata directly from the Linux kernel, computes real-time CPU utilization, monitors memory usage, supports interactive sorting and filtering, and presents the information in a terminal-based user interface using ncurses.

Inspired by utilities such as top and ps, this project was implemented entirely from scratch for learning Operating Systems, Linux System Programming, and Process Management.

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Features

Phase 1 – Process Enumeration

• Enumerates all running processes from the /proc filesystem
• Reads process information directly from /proc/[pid]/status
• Displays:
  • Process ID (PID)
  • Process Name
  • Process State
  • Physical Memory Usage (VmRSS)
• Handles processes that terminate during enumeration safely

Phase 2 – Real-Time Process Monitor

• Real-time CPU utilization calculation
• Live memory monitoring
• Interactive terminal interface using ncurses
• Refreshes every second
• Sort processes by:
  • CPU Usage
  • Memory Usage
  • Process ID
• Filter processes by name
• Highlight high CPU usage processes
• Responsive non-blocking keyboard controls

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Demo

The animation below demonstrates the real-time monitoring interface, highlighting live process updates, interactive sorting capabilities, and terminal-based navigation.

Demonstrated sequence: Sort by CPU (c) → Sort by Memory (m) → Sort by PID (p) → Exit (q)

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How It Works

The monitor gathers information directly from the Linux kernel without relying on external utilities.

Process Information

Reads:

/proc/[pid]/status

to obtain:

• Process Name
• Process State
• Resident Memory (VmRSS)

CPU Utilization

Reads:

/proc/[pid]/stat

to obtain:

• User CPU Time
• Kernel CPU Time

Reads:

/proc/stat

to obtain total CPU time.

CPU usage is computed by comparing two snapshots separated by one second.

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Technologies Used

• C
• Linux
• POSIX APIs
• /proc Filesystem
• ncurses
• GCC

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Linux Concepts Demonstrated

• Process Management
• Linux /proc Virtual Filesystem
• System Calls
• File I/O
• Directory Traversal
• Terminal User Interfaces (TUI)
• CPU Scheduling Statistics
• Memory Monitoring
• Process Enumeration
• Real-Time Monitoring

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Project Structure

ProcessMonitor/
│
├── phase1.c          # Process enumeration
├── phase2.c          # Real-time process monitor
├── README.md
├── LICENSE
└── .gitignore

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Building

Phase 1

gcc phase1.c -o phase1

Phase 2

gcc phase2.c -o phase2 -lncurses

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Running

Phase 1

./phase1

Phase 2

./phase2

Filter by process name:

./phase2 chrome

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Keyboard Controls

Key	Action
c	Sort by CPU Usage
m	Sort by Memory Usage
p	Sort by PID
q	Quit

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Sample Output

PID      NAME                 STATE    CPU%    MEMORY(KB)

2312     chrome               S        21.4      218432
1821     gnome-shell          S         8.6      174020
1120     systemd              S         0.2       14384
...

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Skills Demonstrated

• Linux System Programming
• Operating Systems
• Process Management
• Terminal UI Development
• Parsing Kernel Data Structures
• File Handling
• Data Structures
• Sorting Algorithms
• Real-Time System Monitoring
• C Programming

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Future Improvements

• Multi-core CPU utilization
• Process tree visualization
• Thread information
• Network connection monitoring
• Per-process disk I/O statistics
• Search inside the interface
• Interactive process termination
• Export statistics to CSV
• Color themes
• Historical CPU graphs

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Learning Outcomes

This project was built to gain practical experience with:

• Linux process management
• Operating System internals
• The /proc virtual filesystem
• CPU usage calculation
• Memory monitoring
• Real-time terminal applications
• Linux system programming in C

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License

This project is licensed under the MIT License.

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Author

Teja Sai Eswar

B.Tech, Department of Electronics and Electrical Communication Engineering

Indian Institute of Technology Kharagpur