Basic working version with README.md

Author: plars

README.md

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+# PortCheck
+
+Just a simple ping-like tool that will also take a port argument.  This
+is useful if you not only want to see if a host is up, but if a specific
+service on that host is up.
+
+```
+Usage:
+    portcheck [options] HOST PORT
+
+Options:
+  -count int
+    	Number of packets to send (default 1)
+```
+
+## Installation
+
+### Building from local repo
+To build portcheck from your local repo, run:
+```
+go build ./...
+```
+

cmd/portcheck/main.go

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+/*
+Simple tool to check whether a port is active, and keep checking
+it like ping
+
+Written by:
+  Paul Larson <pwlars@gmail.com>
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net"
+	"os"
+	"time"
+)
+
+type Args struct {
+	host  string
+	port  string
+	count int
+}
+
+func getArgs() Args {
+	var args Args
+	count := flag.Int("count", 1, "Number of packets to send")
+	flag.Parse()
+	if flag.NArg() != 2 {
+		usage()
+		os.Exit(1)
+	}
+	args.host = flag.Arg(0)
+	args.port = flag.Arg(1)
+	args.count = *count
+	return args
+}
+
+func usage() {
+	fmt.Printf("Usage: %s [options] HOST PORT\n\n", os.Args[0])
+	fmt.Println("Options:")
+	flag.PrintDefaults()
+}
+
+func main() {
+	args := getArgs()
+	for i := 0; i < args.count; i++ {
+		fmt.Printf("%d %s:%s - %s\n", i, args.host, args.port, connect(args.host, args.port))
+		time.Sleep(time.Second)
+	}
+}
+
+func connect(host, port string) string {
+	timeout := time.Second
+	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, port), timeout)
+	if err != nil {
+		return "Down"
+	}
+	if conn == nil {
+		return "Down"
+	}
+	conn.Close()
+	return "Up"
+}

go.mod

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+module github.com/plars/portcheck
+
+go 1.18