From d047ea9eb62367e0d03a5eba1411c1485e01bf34 Mon Sep 17 00:00:00 2001
From: Igor V Belousov <igor@belousovv.ru>
Date: Thu, 18 Nov 2021 20:46:20 +0300
Subject: [PATCH] Chapter 1 - dup3

---
 ch1/dup3.go | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 ch1/dup3.go

diff --git a/ch1/dup3.go b/ch1/dup3.go
new file mode 100644
index 0000000..935a9b5
--- /dev/null
+++ b/ch1/dup3.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+)
+
+func main() {
+	counts := make(map[string]int)
+	for _, filename := range os.Args[1:] {
+		data, err := ioutil.ReadFile(filename)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "dup3: %v\v", err)
+			continue
+		}
+		for _, line := range strings.Split(string(data), "\n") {
+			counts[line]++
+		}
+	}
+	for line, n := range counts {
+		if n > 1 {
+			fmt.Printf("%d\t%s\n", n, line)
+		}
+	}
+}
\ No newline at end of file