add version subcommand

build.sh

@@ -16,7 +16,7 @@ echo
 # use bundled versions
 export GOPATH=`godep path`:$GOPATH
 
-gox -osarch="darwin/amd64 linux/amd64 linux/arm"
+gox -ldflags "-X main.version $VERSION" -osarch="darwin/amd64 linux/amd64 linux/arm"
 
 mkdir $VERSION
 

version.go

@@ -0,0 +1,29 @@
+package main
+
+import "fmt"
+
+type VersionCommand struct {
+	// nothing yet
+}
+
+var versionCommand VersionCommand
+
+var version string
+
+func (x *VersionCommand) Execute(args []string) error {
+
+	if len(version) == 0 {
+		fmt.Println("unknown version, compiled from git")
+	} else {
+		fmt.Println("version:", version)
+	}
+
+	return nil
+}
+
+func init() {
+	parser.AddCommand("version",
+		"Print the version number.",
+		"",
+		&versionCommand)
+}