storj-sim: add option to print a single variable (#1720)

cmd/storj-sim/main.go

@@ -66,7 +66,7 @@ func main() {
 				return networkExec(&flags, args, "run")
 			},
 		}, &cobra.Command{
-			Use:   "env",
+			Use:   "env [name]",
 			Short: "print environment variables",
 			RunE: func(cmd *cobra.Command, args []string) (err error) {
 				return networkEnv(&flags, args)

cmd/storj-sim/network.go

@@ -70,6 +70,19 @@ func networkEnv(flags *Flags, args []string) error {
 		}
 	}
 
+	if len(args) == 1 {
+		envprefix := strings.ToUpper(args[0] + "=")
+		// find the environment value that the environment variable is set to
+		for _, env := range processes.Env() {
+			if strings.HasPrefix(strings.ToUpper(env), envprefix) {
+				fmt.Println(env[len(envprefix):])
+				return nil
+			}
+		}
+
+		return nil
+	}
+
 	for _, env := range processes.Env() {
 		fmt.Println(env)
 	}