Linux System Monitor

A modular terminal-based Linux system monitor written entirely in C, built as a systems programming portfolio project. Inspired by tools like top and htop, it collects real-time system information directly from the Linux kernel using the /proc and /sys filesystems together with POSIX APIs, without relying on third-party libraries.

The project demonstrates low-level Linux programming concepts including process management, filesystem parsing, terminal applications, signals, logging, configuration handling, and modular software design.

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Features

• ✅ System Information
• ✅ CPU Monitoring
• ✅ Memory Monitoring
• ✅ Disk Monitoring
• ✅ Process Monitoring
• ✅ Network Monitoring
• ✅ Logged-in Users
• ✅ Live Refresh Mode
• ✅ Command-Line Interface
• ✅ ANSI Colored Output
• ✅ Configuration File Support
• ✅ Timestamped Logging
• ✅ Process Control (SIGTERM / SIGKILL)
• ✅ Modular Architecture
• ✅ Zero Compiler Warnings (-Wall -Wextra -Werror)
• ✅ Compatible with Linux and WSL2

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Screenshots

Main Dashboard

Displays real-time system information including CPU, memory, disk, processes, network interfaces, and logged-in users.

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Command-Line Interface

Shows all supported command-line options for live refresh, sorting, logging, configuration, and process management.

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Technologies Used

• C17
• POSIX APIs
• Linux /proc filesystem
• Linux /sys filesystem
• GNU Make
• GCC
• ANSI Escape Codes

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Project Structure

linux-system-monitor/
│
├── docs/
│   ├── screenshot-main.png
│   └── screenshot-help.png
│
├── include/
│   ├── cli.h
│   ├── color.h
│   ├── config.h
│   ├── cpu.h
│   ├── disk.h
│   ├── log.h
│   ├── mem.h
│   ├── net.h
│   ├── process.h
│   ├── sysinfo.h
│   └── users.h
│
├── modules/
│   ├── cli.c
│   ├── color.c
│   ├── config.c
│   ├── cpu.c
│   ├── disk.c
│   ├── log.c
│   ├── mem.c
│   ├── net.c
│   ├── process.c
│   ├── sysinfo.c
│   └── users.c
│
├── src/
│   └── main.c
│
├── build/
├── Makefile
├── LICENSE
├── .gitignore
└── README.md

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Requirements

• Linux (or WSL2)
• GCC with C17 support
• GNU Make

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Building

Clone the repository:

git clone https://github.com/SamRepository25/Linux-System-Monitor.git
cd Linux-System-Monitor

Build:

make

Clean build artifacts:

make clean

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Usage

Run the monitor:

./build/sysmon

Show help:

./build/sysmon -h

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Command-Line Options

Option	Description
-h	Show help message
-r <seconds>	Enable live refresh mode
-n <count>	Stop after a specified number of refreshes
-t <rows>	Number of process rows to display
-s <c/m/p>	Sort processes by CPU, memory, or PID
-k <PID>	Send SIGTERM to a process
-K <PID>	Send SIGKILL to a process
-l <file>	Append timestamped summaries to a log file
-x	Disable colored output

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Configuration File

The monitor automatically loads a sysmon.conf file if present.

Example:

refresh=2
rows=10
sort=m
color=off

Configuration precedence:

Built-in Defaults
        ↓
sysmon.conf
        ↓
Command-Line Arguments

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Example Output

Status: CPU 4.1% MEM 32.8% DISK(/) 56.4%

=== System Information ===
Hostname      : DELLG15
Kernel        : Linux 6.x
Architecture  : x86_64

=== CPU Information ===
Model         : Intel Core i5
Usage         : 4.1%

=== Memory Information ===
Used RAM      : 2.5 GB (32%)

=== Processes ===
PID     NAME             CPU%    MEM%
1452    firefox          8.1     6.4
3274    code             4.2     5.1

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Architecture

                 Linux Kernel
                        │
        ┌───────────────┴───────────────┐
        │                               │
   POSIX APIs                  /proc & /sys
        │                               │
        └───────────────┬───────────────┘
                        │
                 Monitoring Modules
                        │
                CLI / Terminal Output

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Skills Demonstrated

• Linux Systems Programming
• C Programming
• POSIX APIs
• /proc and /sys Filesystems
• Process Management
• Signal Handling
• Terminal Application Development
• Configuration File Parsing
• Logging
• Modular Software Design
• Build Automation with GNU Make
• Git & GitHub Workflow

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Future Improvements

Potential future enhancements:

• Interactive ncurses interface
• Process search and filtering
• CPU usage graphs
• Memory usage bars
• Export to JSON/CSV
• Temperature sensor monitoring
• Docker/container monitoring
• GPU statistics

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License

This project is licensed under the MIT License.

See the LICENSE file for details.

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Author

B SIMAK AHMED

Computer Science & Engineering Student

GitHub: https://github.com/SamRepository25