scan line

main.go

package main

import (
	"bufio"
	"flag"
	"fmt"
	"os"
	"strings"
)

func ReadWantedLines(filename string) chan string {
	yield := make(chan string, 1)
	go func() {
		f, err := os.Open(filename)
		if err != nil {
			fmt.Printf("error opening file: %v\n", err)
		}

		defer func() {
			f.Close()
			close(yield)
		}()

		scanner := bufio.NewScanner(f)
		for scanner.Scan() {
			s := scanner.Text()
			fmt.Println("read s=", s)
			if strings.HasPrefix("wanted=", s) {
				fmt.Println("wanted s=", s)
				yield <- s
			}
		}
	}()
	return yield
}

func NonComplexProcess(s string) string {
	return s
}

func main() {
	var filename string
	flag.StringVar(&filename, "f", "", "a filename")
	flag.Parse()
	for s := range ReadWantedLines(filename) {
		fmt.Println(s)
		if strings.HasPrefix(s, "wanted=") {
			message := NonComplexProcess(s)
			fmt.Println(message)
		}
	}
	fmt.Println("finished")
}