diff --git a/pkg/devcontainer/config/substiture_test.go b/pkg/devcontainer/config/substiture_test.go
new file mode 100644
index 000000000..fe026b9bd
--- /dev/null
+++ b/pkg/devcontainer/config/substiture_test.go
@@ -0,0 +1,32 @@
+package config
+
+import (
+ "testing"
+ "fmt"
+)
+
+func TestLookupValue(t *testing.T) {
+ tests := []struct {
+  args     []string
+  match    string
+  want     string
+ }{
+  {args: []string{}, match: "", want: ""},
+  {args: []string{"foz"}, match: "${env.foz}", want: ""},
+  {args: []string{"foo","biz"}, match: "${env.foo:biz}", want: "bar"},
+  {args: []string{"baz","bar"}, match: "${env.baz:bar}", want: "bar"},
+  {args: []string{"baz","biz","buz"}, match: "${env.baz:biz:buz}", want: "biz:buz"},
+ }
+
+ localVar := map[string]string{
+ 	"foo": "bar",
+ }
+
+ for i, tt := range tests {
+  t.Run(fmt.Sprintf("#%d", i), func(t *testing.T) {
+   if got := lookupValue(false, localVar, tt.args, tt.match); got != tt.want {
+    t.Errorf("lookupValue(%v, %v, %v, %v) = %v, want %v", false, localVar, tt.args, tt.match, got, tt.want)
+   }
+  })
+ }
+}
diff --git a/pkg/devcontainer/config/substitute.go b/pkg/devcontainer/config/substitute.go
index 22945d170..600c44c27 100644
--- a/pkg/devcontainer/config/substitute.go
+++ b/pkg/devcontainer/config/substitute.go
@@ -141,7 +141,7 @@ func lookupValue(isWindows bool, env map[string]string, args []string, match str
 		}
 
 		if len(args) > 1 {
-			defaultValue := args[1]
+			defaultValue := strings.Join(args[1:], ":")
 			return defaultValue
 		}