Move version out of main.go

cmd/root.go

@@ -8,13 +8,12 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var Version string
 var versionCmd = &cobra.Command{
 	Use:    "version",
 	Short:  "Show version",
 	Hidden: true,
 	Run: func(cmd *cobra.Command, args []string) {
-		cmd.Println(cmd.Root().Name(), Version)
+		cmd.Println(cmd.Root().Name(), version)
 	},
 }
 

cmd/version.go

@@ -0,0 +1,6 @@
+package cmd
+
+import _ "unsafe"
+
+//go:linkname version main.version
+var version string = "<unknown>"

main.go

@@ -6,10 +6,7 @@ import (
 	"github.com/USTC-vlab/vct/cmd"
 )
 
-var version string = "<unknown>"
-
 func main() {
-	cmd.Version = version
 	if err := cmd.MakeCmd().Execute(); err != nil {
 		os.Exit(1)
 	}