diff --git a/.github/dockerhub.png b/.github/dockerhub.png
new file mode 100644
index 0000000..a559a38
Binary files /dev/null and b/.github/dockerhub.png differ
diff --git a/README.md b/README.md
index 7ea38ae..977bd09 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,10 @@
-# nginx-formatter
-Nginx Conf Formatter.
+# Nginx Formatter
+
+Nginx configuration formatter under 10MB size.
+
+
+## Docker
+
+<img src=".github/dockerhub.png" width="240" >
+
+- https://hub.docker.com/r/soulteary/nginx-formatter
diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 0000000..7826e80
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,13 @@
+# Security Policy
+
+## Supported Versions
+
+All releases accept security reports, updates.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| *       | :white_check_mark: |
+
+## Reporting a Vulnerability
+
+If you find any security issues, welcome to file an issue or submit a PR directly.
diff --git a/internal/formatter/beautifier.js b/internal/formatter/beautifier.js
index f9f7059..93c3d6a 100644
--- a/internal/formatter/beautifier.js
+++ b/internal/formatter/beautifier.js
@@ -173,6 +173,16 @@ function add_empty_line_after_nginx_directives(lines) {
   return output.reverse();
 }
 
+function fixDollarVar(lines) {
+  const placeHolder = `[dollar]`;
+  return lines.map((line) => {
+    while (line.indexOf(placeHolder) !== -1) {
+      line = line.replace(placeHolder, "$");
+    }
+    return line;
+  });
+}
+
 var options = { INDENTATION: "\t" };
 
 function perform_indentation(lines) {
@@ -205,5 +215,6 @@ function FormatNginxConf(text, indentation = "  ") {
   lines = join_opening_bracket(lines);
   lines = perform_indentation(lines);
   lines = add_empty_line_after_nginx_directives(lines);
+  lines = fixDollarVar(lines);
   return fold_empty_brackets(lines);
 }
diff --git a/internal/updater/updater.go b/internal/updater/updater.go
index 3342264..ea504d9 100644
--- a/internal/updater/updater.go
+++ b/internal/updater/updater.go
@@ -4,9 +4,62 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 )
 
+func EncodeEscapeChars(s string) string {
+	return strings.ReplaceAll(strings.ReplaceAll(strings.ReplaceAll(strings.ReplaceAll(s, `\t`, `【\\】t`), `\s`, `【\\】s`), `\r`, `【\\】r`), `\n`, `【\\】n`)
+}
+
+func DecodeEscapeChars(s string) string {
+	return strings.ReplaceAll(strings.ReplaceAll(strings.ReplaceAll(strings.ReplaceAll(s, `【\】t`, `\t`), `【\】s`, `\s`), `【\】r`, `\r`), `【\】n`, `\n`)
+}
+
+// scenes:
+//
+//		return 200 "1" ;
+//		return 200 "1";
+//		return   "1" ;
+//		return  200;
+//		return  "aaa\naa";
+//		return  200 "a\n"   ;
+//	 	return BACKEND\n;
+func FixReturn(s string) string {
+	var scene1 = regexp.MustCompile(`return\s+(\d+)\s(\S+)\s*;`)
+	var scene2 = regexp.MustCompile(`return\s+(\d+)\s"(\S+)"\s*;`)
+	var scene3 = regexp.MustCompile(`return\s+(\S+)\s*;`)
+	var scene4 = regexp.MustCompile(`return\s+"(\S+)"\s*;`)
+	var scene5 = regexp.MustCompile(`return\s+(\d+)\s*;`)
+
+	if scene1.MatchString(s) {
+		if scene2.MatchString(s) { // eg: `return 200 "ok";`
+			s = scene2.ReplaceAllString(s, "return $1 \"$2\";")
+		} else { // eg: `return 200 $content;`
+			s = scene1.ReplaceAllString(s, "return $1 \"$2\";")
+		}
+	} else if scene3.MatchString(s) {
+		if scene5.MatchString(s) { // eg: `return 200;`
+			s = scene5.ReplaceAllString(s, "return $1;")
+		} else if scene4.MatchString(s) { // eg: `return "ok";`
+			s = scene4.ReplaceAllString(s, "return \"$1\";")
+		} else { // eg: `return BACKEND\n;`
+			found := scene3.FindString(s)
+			if !(strings.HasPrefix(found, `"`) && strings.HasSuffix(found, `"`)) {
+				s = scene3.ReplaceAllString(s, "return $1;")
+			} else {
+				s = scene3.ReplaceAllString(s, "return \"$1\";")
+			}
+		}
+	}
+	return s
+}
+
+func FixVars(s string) string {
+	s = regexp.MustCompile(`(\$)(\{\S+?\})`).ReplaceAllString(s, "[dollar]$2")
+	return s
+}
+
 func UpdateConfInDir(rootDir string, fn func(s string) (string, error)) error {
 	if rootDir == "" {
 		return fmt.Errorf("scandir is empty")
@@ -23,12 +76,12 @@ func UpdateConfInDir(rootDir string, fn func(s string) (string, error)) error {
 				return err
 			}
 
-			modifiedData, err := fn(string(data))
+			modifiedData, err := fn(FixVars(FixReturn(EncodeEscapeChars(string(data)))))
 			if err != nil {
 				return err
 			}
 
-			err = os.WriteFile(path, []byte(modifiedData), info.Mode())
+			err = os.WriteFile(path, []byte(DecodeEscapeChars(modifiedData)), info.Mode())
 			if err != nil {
 				return err
 			}