Accept multiple files

examples/markdown.feature

@@ -68,3 +68,15 @@ Feature: Markdown
     Then the exit status should be 1
     And the stderr should contain "OK"
     And the stderr should contain "ERROR"
+
+  Scenario: Check 2 markdown files
+    Given a file named "foo.md" with:
+    """
+    [Google](https://google.com)
+    """
+    And a file named "bar.md" with:
+    """
+    [Yahoo](https://yahoo.com)
+    """
+    When I successfully run `linkcheck foo.md bar.md`
+    Then the stdout should contain exactly ""

main.go

@@ -21,22 +21,43 @@ func main() {
 	}()
 
 	args := getArgs()
+	fs := args["<filenames>"].([]string)
+	bs := make(chan bool, len(fs))
+	c := newURLChecker(5*time.Second, args["--verbose"].(bool))
+
+	for _, f := range fs {
+		go func(f string) {
+			bs <- checkFile(c, f)
+		}(f)
+	}
+
+	ok := true
+
+	for i := 0; i < len(fs); i++ {
+		ok = <-bs && ok
+	}
+
+	if !ok {
+		os.Exit(1)
+	}
+}
 
-	bs, err := ioutil.ReadFile(args["<filename>"].(string))
+func checkFile(c urlChecker, f string) bool {
+	bs, err := ioutil.ReadFile(f)
 
 	if err != nil {
-		panic(err)
+		printToStderr(err.Error())
+		return false
 	}
 
 	n, err := html.Parse(strings.NewReader(mark.Render(string(bs))))
 
 	if err != nil {
-		panic(err)
+		printToStderr(err.Error())
+		return false
 	}
 
-	if !newURLChecker(5*time.Second, args["--verbose"].(bool)).CheckMany(extractURLs(n)) {
-		os.Exit(1)
-	}
+	return c.CheckMany(extractURLs(n))
 }
 
 func extractURLs(n *html.Node) []string {
@@ -75,7 +96,7 @@ func getArgs() map[string]interface{} {
 	usage := `Link checker for Markdown and HTML
 
 	Usage:
-	linkcheck [-v] <filename>
+	linkcheck [-v] <filenames>...
 
 	Options:
 	-v, --verbose  Be verbose`