Use actual binary name instead of hardcoding it

Signed-off-by: Radek Simko <radek.simko@gmail.com>

help.go

@@ -1,13 +1,18 @@
 package main
 
-import "github.com/codegangsta/cli"
+import (
+	"os"
+	"path"
+
+	"github.com/codegangsta/cli"
+)
 
 func init() {
-
+	// See https://github.com/codegangsta/cli/pull/171/files
 	cli.CommandHelpTemplate = `{{$DISCOVERY := or (eq .Name "manage") (eq .Name "join") (eq .Name "list")}}NAME:
    {{.Name}} - {{.Usage}}
 USAGE:
-   swarm {{.Name}}{{if .Flags}} [options]{{end}} {{if $DISCOVERY}}<discovery>{{end}}{{if .Description}}
+   ` + path.Base(os.Args[0]) + ` {{.Name}}{{if .Flags}} [options]{{end}} {{if $DISCOVERY}}<discovery>{{end}}{{if .Description}}
 DESCRIPTION:
    {{.Description}}{{end}}{{if $DISCOVERY}}
 ARGUMENTS:

join.go

@@ -17,7 +17,7 @@ func checkAddrFormat(addr string) bool {
 func join(c *cli.Context) {
 	dflag := getDiscovery(c)
 	if dflag == "" {
-		log.Fatal("discovery required to join a cluster. See 'swarm join --help'.")
+		log.Fatalf("discovery required to join a cluster. See '%s join --help'.", c.App.Name)
 	}
 
 	d, err := discovery.New(dflag, c.Int("heartbeat"))

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"path"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/codegangsta/cli"
@@ -18,7 +19,7 @@ import (
 
 func main() {
 	app := cli.NewApp()
-	app.Name = "swarm"
+	app.Name = path.Base(os.Args[0])
 	app.Usage = "a Docker-native clustering system"
 	app.Version = "0.1.0"
 	app.Author = ""
@@ -78,7 +79,7 @@ func main() {
 			Action: func(c *cli.Context) {
 				dflag := getDiscovery(c)
 				if dflag == "" {
-					log.Fatal("discovery required to list a cluster. See 'swarm list --help'.")
+					log.Fatalf("discovery required to list a cluster. See '%s list --help'.", c.App.Name)
 				}
 
 				d, err := discovery.New(dflag, 0)

manage.go

@@ -83,7 +83,7 @@ func manage(c *cli.Context) {
 
 	dflag := getDiscovery(c)
 	if dflag == "" {
-		log.Fatal("discovery required to manage a cluster. See 'swarm manage --help'.")
+		log.Fatalf("discovery required to manage a cluster. See '%s manage --help'.", c.App.Name)
 	}
 
 	s, err := strategy.New(c.String("strategy"))