Flag to display version of the application

Makefile

@@ -0,0 +1,41 @@
+PREFIX?=$(shell pwd)
+BUILDTAGS=
+
+VERSION = 0.2.0
+
+.PHONY: clean all fmt vet lint build test install static
+.DEFAULT: default
+
+all: clean build fmt lint test vet install
+
+build:
+	@echo "+ $@"
+	@go build -tags "$(BUILDTAGS) cgo" -ldflags "-w -extldflags -static -X main.version=$(VERSION)" -o untrak .
+
+static:
+	@echo "+ $@"
+	CGO_ENABLED=1 go build -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static -X main.version=$(VERSION)" -o untrak .
+
+fmt:
+	@echo "+ $@"
+	@gofmt -s -l . | grep -v vendor | tee /dev/stderr
+
+lint:
+	@echo "+ $@"
+	@golint ./... | grep -v vendor | tee /dev/stderr
+
+test: fmt lint vet
+	@echo "+ $@"
+	@go test -v -tags "$(BUILDTAGS) cgo" $(shell go list ./... | grep -v vendor)
+
+vet:
+	@echo "+ $@"
+	@go vet $(shell go list ./... | grep -v vendor)
+
+clean:
+	@echo "+ $@"
+	@rm -rf untrack
+
+install:
+	@echo "+ $@"
+	@go install .

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	"log"
 	"os"
 	"strings"
@@ -16,12 +17,28 @@ import (
 	"github.com/yanc0/untrak/config"
 )
 
+const (
+	// BANNER is what is printed for help/info output.
+	BANNER = "Untrack - %s\n"
+)
+
+var (
+	// version indicates which version of the binary is running.
+	version string
+)
+
 func main() {
 	// Flags, command line parameters
 	var cfgPathOpt = flag.String("config", "./untrak.yaml", "untrak Config Path")
 	var outputOpt = flag.String("o", "text", "Output format")
+	var versionOpt = flag.Bool("version", false, "Print version of the application")
 	flag.Parse()
 
+	if *versionOpt {
+		fmt.Printf("%s\n", version)
+		os.Exit(0)
+	}
+
 	var wg sync.WaitGroup
 	var resourcesIn []*kubernetes.Resource
 	var resourcesOut []*kubernetes.Resource