adds version via ldflags to circleci build

.circleci/config.yml

@@ -15,7 +15,11 @@ jobs:
       - run: go test -v $(go list ./...)
       - run: go build .
       - run: ./golcov --help
-      - run: gox -output="dist/{{.Dir}}_{{.OS}}_{{.Arch}}" --osarch="linux/386 linux/amd64 linux/arm darwin/386 darwin/amd64 windows/386 windows/adm64" 
+      - run: |
+          gox \
+            -output="dist/{{.Dir}}_{{.OS}}_{{.Arch}}" \
+            -osarch="linux/386 linux/amd64 linux/arm darwin/386 darwin/amd64 windows/386 windows/adm64" \
+            -ldflags="-X main.version=$CIRCLE_TAG -X main.revision=$CIRCLE_SHA1"
       - run: cd dist && sha256sum golcov* | tee sha256sums.txt
       - persist_to_workspace:
           root: ./dist

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"os"
 
@@ -17,6 +18,7 @@ func main() {
 		Usage: "Runs go test with default coverage options for each package and writes it to standard out",
 		Commands: []cli.Command{
 			testCmd,
+			versionCmd,
 		},
 		Before: setup,
 		Action: testAction,
@@ -33,6 +35,8 @@ func main() {
 var (
 	osa      osadapter.OS
 	goBinary string
+	version  string = "dev"
+	revision string = "dev"
 )
 
 var testCmd = cli.Command{
@@ -74,3 +78,11 @@ func createTests(pkgs ...string) (tests []test.Test) {
 	}
 	return
 }
+
+var versionCmd = cli.Command{
+	Name:  "version",
+	Usage: "displays the version",
+	Action: func(c *cli.Context) {
+		fmt.Printf("%s version: %s (%s)\n", c.App.Name, version, revision)
+	},
+}