diff --git a/source/build.go b/source/build.go
index efab7d4..b8dc3a6 100644
--- a/source/build.go
+++ b/source/build.go
@@ -30,8 +30,14 @@ func ParseBuildScript(str string) (BuildScript, error) {
 			continue
 		}
 		parts := strings.Split(line, " ")
-		if _, err := exec.LookPath(parts[0]); err != nil {
-			return nil, fmt.Errorf("line %d: %w", i, err)
+		for _, part := range parts {
+			if strings.Contains(part, "=") {
+				continue
+			}
+			if _, err := exec.LookPath(part); err != nil {
+				return nil, fmt.Errorf("line %d: %w", i, err)
+			}
+			break
 		}
 		out = append(out, BuildStep(line))
 	}
diff --git a/source/build_test.go b/source/build_test.go
index e176e2c..04dc5c9 100644
--- a/source/build_test.go
+++ b/source/build_test.go
@@ -54,6 +54,13 @@ func TestParseBuildScript(t *testing.T) {
 			input:   "thisfiledoesnotexist --xx --yy",
 			wantErr: true,
 		},
+		{
+			name:  "EnvVar",
+			input: "FOO=bar echo $FOO",
+			want: BuildScript{
+				"FOO=bar echo $FOO",
+			},
+		},
 		{
 			name:  "Empty",
 			input: "",