diff --git a/builder/dockerfile/shell/envVarTest b/builder/dockerfile/shell/envVarTest
index 6071caebd2..08011801c5 100644
--- a/builder/dockerfile/shell/envVarTest
+++ b/builder/dockerfile/shell/envVarTest
@@ -174,6 +174,22 @@ A|$9                        |
 A|${9}                      |
 A|${9:+bbb}                 |
 A|${9:-bbb}                 |     bbb
+A|$999                      |
+A|${999}                    |
+A|${999:+bbb}               |
+A|${999:-bbb}               |     bbb
+A|$999aaa                   |     aaa
+A|${999}aaa                 |     aaa
+A|${999:+bbb}aaa            |     aaa
+A|${999:-bbb}aaa            |     bbbaaa
+A|$001                      |
+A|${001}                    |
+A|${001:+bbb}               |
+A|${001:-bbb}               |     bbb
+A|$001aaa                   |     aaa
+A|${001}aaa                 |     aaa
+A|${001:+bbb}aaa            |     aaa
+A|${001:-bbb}aaa            |     bbbaaa
 
 # Special parameters won't be set in the Dockerfile:
 # http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_05_02
@@ -181,6 +197,11 @@ A|$@                        |
 A|${@}                      |
 A|${@:+bbb}                 |
 A|${@:-bbb}                 |     bbb
+A|$@@@                      |     @@
+A|$@aaa                     |     aaa
+A|${@}aaa                   |     aaa
+A|${@:+bbb}aaa              |     aaa
+A|${@:-bbb}aaa              |     bbbaaa
 A|$*                        |
 A|${*}                      |
 A|${*:+bbb}                 |
diff --git a/builder/dockerfile/shell/lex.go b/builder/dockerfile/shell/lex.go
index a51a2665aa..0c80900ade 100644
--- a/builder/dockerfile/shell/lex.go
+++ b/builder/dockerfile/shell/lex.go
@@ -318,7 +318,15 @@ func (sw *shellWord) processName() string {
 
 	for sw.scanner.Peek() != scanner.EOF {
 		ch := sw.scanner.Peek()
-		if name.Len() == 0 && (unicode.IsDigit(ch) || isSpecialParam(ch)) {
+		if name.Len() == 0 && unicode.IsDigit(ch) {
+			for sw.scanner.Peek() != scanner.EOF && unicode.IsDigit(sw.scanner.Peek()) {
+				// Keep reading until the first non-digit character, or EOF
+				ch = sw.scanner.Next()
+				name.WriteRune(ch)
+			}
+			return name.String()
+		}
+		if name.Len() == 0 && isSpecialParam(ch) {
 			ch = sw.scanner.Next()
 			return string(ch)
 		}