mailq-inspector/shell.go

package main

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

func interactiveShell(reader io.Reader, writer io.Writer) {
	fmt.Fprintln(writer, "Let's try an interactive shell!")
	scanner := bufio.NewScanner(reader)
	for {
		var quitShell bool = false
		fmt.Fprint(writer, "> ")
		if !scanner.Scan() {
			break
		}
		text := strings.Trim(scanner.Text(), " ")
		textFields := strings.Fields(text)
		if len(textFields) == 0 {
			continue
		}
		cmd := textFields[0]
		fmt.Fprintf(writer, "DEBUG - Read input: %q\n", textFields)

		switch cmd {
		case "help", "?":
			printHelp(os.Stdout)
		case "exit", "quit":
			quitShell = true
		default:
			fmt.Fprintf(writer, "Unknown command '%s'\n", cmd)
			fmt.Fprintln(writer, "Use 'help' to display help command")
		}
		if quitShell == true {
			break
		}
	}
	fmt.Fprintln(writer, "\nGoodbye!\n")
}

func printHelp(writer io.Writer) {
	fmt.Fprintln(writer, "Available commands:")
	fmt.Fprintln(writer, "?, help: display this output")
	fmt.Fprintln(writer, "exit, quit: quit this program")
}