🚀 Linux System Monitor (sysmon)

A high-performance, lightweight, and native system monitor for Linux.

sysmon is a C-based utility designed for users who need real-time system insights without the overhead of heavy monitoring suites. By reading directly from the kernel's /proc filesystem, it provides raw, accurate data with minimal CPU and RAM impact.

Why use sysmon?

• Zero Bloat: Written in pure C with no external dependencies.
• Data-Ready: Outputs metrics in JSON Lines (.jsonl) format, perfect for automation and data pipelines.
• Smart Logging: Features built-in O(1) log rotation to ensure your storage never fills up unexpectedly.
• Native Performance: Interacts directly with the Linux kernel for maximum efficiency.

🛠 User Guide

🔨 Manual Build from Source

If you prefer building it yourself or want to customize the code:

1. Navigate to the source directory:

cd linux-sysmon

2. Compile the project:

make       #for x64
make x86   #for x86
make arm64 #for arm64

3. Install to your system path:

sudo make install

4. Run the monitor: Simply type sysmon in your terminal.

📈 Accessing Your Data

Logs are stored every 5 seconds in ~/.status/status.json. You can watch the metrics live using:

tail -f ~/.status/status.json

---

🚩 Flags and Configuration

1. GENERAL (3 flags)

Flag	Function	Description
-h, --help	Help	Show help message
-v, --version	Version	Show version information
-V, --verbose	Verbose	Enable debug mode
-c, --config	Config	Load configuration file

2. TIMING (3 flags)

Flag	Function	Default
-i, --interval <seconds>	Sampling interval	5 seconds
--cpu-delay <us>	CPU sampling delay	200000 µs
-1, --one-shot	Run once then exit	-

3. LOGGING (5 flags)

Flag	Function	Default
-l, --logdir <dir>	Log directory	~/.status
-f, --logfile <name>	Log filename	status.json
-o, --output <path>	Override full output path	-
-m, --maxsize <MB>	Log rotation size	10 MB
--no-log	Disable file logging	false

4. DAEMON (2 flags)

Flag	Function
-d, --daemon	Run in background
-p, --pidfile <file>	Path to PID file

5. NETWORK (1 flag)

Flag	Function	Default
-n, --net-interface <iface>	Network interface to monitor	Auto-detect

6. PROCESS (1 flag)

Flag	Function	Default
-t, --top-processes <N>	Show top N processes	0 (disabled)

7. DISK (1 flag)

Flag	Function	Default
--disk-mount <path>	Disk mount point to monitor	/

8. DISPLAY (1 flag)

Flag	Function
-q, --quiet	No console output

---

CONFIGURATION VIA FILE

INI Format (sysmon.ini)

interval = 5
cpu_delay = 200000
logdir = ~/.status
logfile = status.json
maxsize = 10
quiet = false
verbose = false
no_log = false
daemon = false
pidfile = 
net-interface = 
disk-mount = /
top-processes = 0
one-shot = false

JSON Format (sysmon.json)

{
    "interval": 5,
    "cpu_delay": 200000,
    "logdir": "~/.status",
    "logfile": "status.json",
    "maxsize": 10,
    "quiet": false,
    "verbose": false,
    "no_log": false,
    "daemon": false,
    "pidfile": "",
    "net-interface": "",
    "disk-mount": "/",
    "top-processes": 0,
    "one-shot": false
}

---

PRACTICAL EXAMPLES

# Normal mode
sysmon

# Daemon mode with custom settings
sysmon -d -i 30 -l /var/log/sysmon -p /var/run/sysmon.pid -q

# Monitor specific interface + top 5 processes
sysmon -n eth0 -t 5 -i 2 -V

# One-time snapshot to file
sysmon -1 -o /tmp/snapshot.json

# Load from config file
sysmon --config /etc/sysmon.ini

# Override config file with CLI flags
sysmon -c sysmon.ini -i 10 -t 5

---

TOTAL NEW ARGUMENTS

18 Arguments Total

• 9 short flags: -h, -v, -i, -d, -l, -f, -m, -o, -n, -q, -c, -p, -t, -1, -V
• 12 long options: --help, --version, --interval, --daemon, --logdir, --logfile, --maxsize, --output, --net-interface, --quiet, --config, --pidfile, --top-processes, --disk-mount, --cpu-delay, --no-log, --one-shot, --verbose

2 Configuration File Formats (INI & JSON)
Fully backward compatible with the original sysmon

---

⚙️ Technical Reference

Project Architecture

The project is structured for simplicity and modularity:

• sysmon.h: Constants, data structures, and function declarations.
• sysmon.c: Core implementation for CPU, RAM, Disk, and Network tracking.
• main.c: Entry point handling the main execution loop and signals.
• Makefile: Standard build instructions.

Monitored Metrics

Category	Data Captured
CPU	Usage % (delta jiffy) and Load Average (1m/5m/15m)
RAM	Total, Used, Free, Available, Cached, and Buffers
Disk	Total, Used, and Free space on the root (/) partition
Network	Active interface, RX (Download) KB/s, and TX (Upload) KB/s
System	Uptime (DD:HH:MM:SS) and precise timestamps

Advanced Configuration

Modify these values in sysmon.h to tune the monitor's behavior:

#define SAMPLE_INTERVAL   5                       // Seconds between samples
#define LOG_MAX_BYTES     (10L * 1024L * 1024L)  // Rotate log at 10 MB

Integration Example (Python)

Easily parse your system logs for custom dashboards or analysis:

import json

with open("/home/user/.status/status.json") as f:
    for line in f:
        entry = json.loads(line)
        print(f"{entry['time']} | CPU: {entry['cpu_usage']}% | "
              f"RAM: {entry['ram']['used']}/{entry['ram']['total']} MB")

📄 Requirements & Licensing

• OS: Linux with /proc filesystem support.
• Compiler: GCC with C11 support (gcc >= 4.9).
• License: Distributed with MIT License. Feel free to fork, modify, and contribute!