All source listed below is under MIT license if no LICENSE file stating different is available.

rtop

A terminal-based system monitoring tool written in C that displays comprehensive system statistics in a dynamic, auto-refreshing interface. rtop is designed as a lightweight alternative to htop with no external dependencies beyond the standard C library.

Features

Real-time system monitoring with configurable refresh interval
Per-core CPU utilization with temperature and frequency display
Memory and swap usage statistics
Process listing sorted by CPU or memory usage
Network interface statistics with RX/TX rates
Disk I/O statistics
Filesystem usage information
Color-coded output for utilization levels
Terminal resize handling
Keyboard controls (q to quit)

Requirements

Linux operating system
GCC compiler (C99 compliant)
Make build system

Building

make

The build produces a single binary rtop with minimal dependencies.

Build Options

make clean      # Remove build artifacts
make debug      # Build with debug symbols
make install    # Install to /usr/local/bin (requires root)

Usage

./rtop [OPTIONS]

Options:
  -d, --delay SECS   Update interval in seconds (default: 1.0)
  -s, --sort MODE    Sort by: cpu (default), mem
  -h, --help         Show help message
  -v, --version      Show version

Examples

./rtop              # Run with default settings
./rtop -d 2         # Update every 2 seconds
./rtop -s mem       # Sort processes by memory usage

Display Sections

Header: Hostname, OS version, kernel, uptime, load averages
CPU: Per-core utilization, total usage, temperature, frequency
Memory: RAM and swap usage with buffer/cache information
Processes: Summary counts (running, sleeping, stopped, zombie)
Network: Interface statistics with IP addresses and transfer rates
Disk I/O: Read/write rates and IOPS per device
Filesystems: Mount points with usage percentages
Process List: Detailed per-process information

Controls

q or Q: Quit the application
Ctrl+C: Terminate

Technical Details

Data Sources

All system information is read from the Linux /proc and /sys filesystems:

/proc/stat - CPU statistics
/proc/meminfo - Memory information
/proc/[pid]/stat - Process information
/proc/net/dev - Network statistics
/proc/diskstats - Disk I/O statistics
/sys/class/thermal/ - Temperature sensors

Performance

Target CPU usage: <5%
Startup time: <100ms
Memory footprint: <10MB RSS
Binary size: ~1.2MB

Project Structure

rtop/
├── include/
│   ├── cpu.h
│   ├── disk.h
│   ├── display.h
│   ├── filesystem.h
│   ├── memory.h
│   ├── network.h
│   ├── process.h
│   ├── system.h
│   └── terminal.h
├── src/
│   ├── cpu.c
│   ├── disk.c
│   ├── display.c
│   ├── filesystem.c
│   ├── main.c
│   ├── memory.c
│   ├── network.c
│   ├── process.c
│   ├── system.c
│   └── terminal.c
├── Makefile
└── README.md

License

This project is provided as-is for educational and personal use.

include
src
.gitignore
CHANGELOG.md
Makefile
README.md
rtop
rtop.md