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 tabbed, auto-refreshing interface. rtop is designed as a lightweight alternative to htop with no external dependencies beyond the standard C library.

Features

Tabbed interface with 5 dedicated views (CPU, Memory, Network, Disk, Process)
Real-time system monitoring with configurable refresh interval
Auto-rotate tabs at configurable interval
Pause mode for copy/paste operations
Per-core CPU utilization with temperature and frequency display
Memory and swap usage statistics with task summary
Process listing sorted by CPU or memory usage
Network interface statistics with RX/TX rates and IP addresses
Disk I/O statistics with IOPS
Filesystem usage information
Color-coded progress bars for utilization levels
Terminal resize handling

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)
  -r, --rotate SECS  Auto-rotate tabs every SECS seconds (0=off, default: 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 -r 5         # Auto-rotate tabs every 5 seconds
./rtop -s mem       # Sort processes by memory usage
./rtop -d 0.5 -r 3  # Fast refresh with 3-second tab rotation

Tabs

Tab	Content
CPU	Per-core utilization bars, temperature, frequency, total usage
Memory	RAM/Swap usage, buffers/cache, task summary (running, sleeping, stopped, zombie)
Network	Interface list with IP addresses, RX/TX rates, total bytes transferred
Disk	Per-device I/O rates, IOPS, filesystem mount points with usage
Process	Detailed process list with PID, user, CPU%, MEM%, command

Controls

Key	Action
Left/Right arrows	Switch between tabs
1-5	Jump directly to tab
ESC	Pause refresh (for copy/paste)
q / Q	Quit the application
Ctrl+C	Terminate

Technical Details

Data Sources

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

Source	Information
`/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
`/sys/devices/system/cpu/`	CPU frequency

Performance

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

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