diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2598560..34800fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,22 +2,19 @@
 
 ## [0.1.3](https://github.com/YieldRay/nrm-lite/compare/v0.1.2...v0.1.3) (2024-03-12)
 
-
 ### Bug Fixes
 
-* fix the --version flag ([9e059ef](https://github.com/YieldRay/nrm-lite/commit/9e059efaf24198123e01307a71e59dfdad09bba2))
+-   fix the --version flag ([9e059ef](https://github.com/YieldRay/nrm-lite/commit/9e059efaf24198123e01307a71e59dfdad09bba2))
 
 ## [0.1.2](https://github.com/YieldRay/nrm-lite/compare/v0.1.1...v0.1.2) (2024-03-11)
 
-
 ### Features
 
-* support timeout for test command ([d14c87d](https://github.com/YieldRay/nrm-lite/commit/d14c87d70a5990dc60c855f5c42883d1d9e8da3e))
+-   support timeout for test command ([d14c87d](https://github.com/YieldRay/nrm-lite/commit/d14c87d70a5990dc60c855f5c42883d1d9e8da3e))
 
 ## 0.1.1 (2024-03-11)
 
-
 ### Features
 
-* add test command ([432f29d](https://github.com/YieldRay/nrm-lite/commit/432f29db4524f64951056970ab44b0917302efa2))
-* initial commit ([ff2c04b](https://github.com/YieldRay/nrm-lite/commit/ff2c04b774b81b849c60a46c18dde2555c51b61e))
+-   add test command ([432f29d](https://github.com/YieldRay/nrm-lite/commit/432f29db4524f64951056970ab44b0917302efa2))
+-   initial commit ([ff2c04b](https://github.com/YieldRay/nrm-lite/commit/ff2c04b774b81b849c60a46c18dde2555c51b61e))
diff --git a/README.md b/README.md
index 1aa07ee..beb0951 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![node-current](https://img.shields.io/node/v/nrm-lite)](https://nodejs.dev/)
 [![install size](https://packagephobia.com/badge?p=nrm-lite)](https://packagephobia.com/result?p=nrm-lite)
 
-Fast and lightweight NpmRegistryManager, for the minimalists.  
+Fast and lightweight Npm [Registry](https://docs.npmjs.com/cli/using-npm/registry) Manager, for the minimalists.  
 Like [dnrm](https://github.com/markthree/dnrm), but in pure Node.js.
 
 [![asciicast](https://asciinema.org/a/646571.svg)](https://asciinema.org/a/646571)
diff --git a/cli.mjs b/cli.mjs
index 81da6c1..78b04fd 100644
--- a/cli.mjs
+++ b/cli.mjs
@@ -7,7 +7,7 @@ import { fileURLToPath } from 'node:url'
 import { dirname } from 'node:path'
 import { getRegistry, setRegistry, getConfigPath } from './config.mjs'
 import { REGISTRIES, speedTest } from './registry.mjs'
-import c, { printRegistries } from './tty.mjs'
+import c, { printRegistries } from './utils.mjs'
 
 // https://nodejs.org/api/util.html#utilparseargsconfig
 const { values, positionals } = parseArgs({
diff --git a/config.mjs b/config.mjs
index edad94f..4f464d8 100644
--- a/config.mjs
+++ b/config.mjs
@@ -1,7 +1,11 @@
 import * as fs from 'node:fs'
 import { writeFile } from 'node:fs/promises'
 import { homedir } from 'node:os'
-import { REGISTRIES, findRegistryFromStream } from './registry.mjs'
+import {
+    REGISTRIES,
+    getRegistryFromStream,
+    setRegistryFromStream,
+} from './registry.mjs'
 import { isFile } from './utils.mjs'
 
 /**
@@ -10,24 +14,13 @@ import { isFile } from './utils.mjs'
  */
 export async function setRegistry(local, registryUrl) {
     const filePath = await getConfigPath(local)
-
-    const fileStream = fs.createReadStream(filePath)
-    const { registry, lines, registryLineNumber } =
-        await findRegistryFromStream(fileStream)
-    const newRegistryLine = `registry=${registryUrl}`
-
-    if (!registry) {
-        lines.push(newRegistryLine)
-    } else if (registry === registryUrl) {
-        // same, do nothing
-        return
-    } else {
-        // number-1 is index
-        lines[registryLineNumber - 1] = newRegistryLine
+    try {
+        const fileStream = fs.createReadStream(filePath)
+        const result = await setRegistryFromStream(fileStream, registryUrl)
+        return writeFile(filePath, result)
+    } catch {
+        return writeFile(filePath, `registry=${registryUrl}`)
     }
-
-    const result = lines.join('\n')
-    return writeFile(filePath, result)
 }
 
 /**
@@ -35,9 +28,13 @@ export async function setRegistry(local, registryUrl) {
  */
 export async function getRegistry(local) {
     const filePath = await getConfigPath(local)
-    const fileStream = fs.createReadStream(filePath)
-    const { registry } = await findRegistryFromStream(fileStream)
-    return registry || REGISTRIES['npm']
+    try {
+        const fileStream = fs.createReadStream(filePath) // the file may not exists
+        return (await getRegistryFromStream(fileStream)) || REGISTRIES['npm']
+    } catch {
+        // when rc file not found, fallback registry to default
+        return REGISTRIES['npm']
+    }
 }
 
 /**
diff --git a/index.mjs b/index.mjs
index d36d219..cb000f0 100644
--- a/index.mjs
+++ b/index.mjs
@@ -1,2 +1,2 @@
-export * from './config.mjs'
-export * from './registry.mjs'
+export { getRegistry, setRegistry, getConfigPath } from './config.mjs'
+export { speedTest } from './registry.mjs'
diff --git a/package.json b/package.json
index f5a5519..bdb2352 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "nrm-lite",
-    "version": "0.1.3",
+    "version": "0.2.0",
     "type": "module",
     "description": "Fast and lightweight NpmRegistryManager, for the minimalists.",
     "main": "index.mjs",
@@ -22,8 +22,8 @@
         "nrml": "cli.mjs"
     },
     "devDependencies": {
-        "@types/node": "^20.11.26",
-        "typescript": "^5.4.2"
+        "@types/node": "^20.14.2",
+        "typescript": "^5.4.5"
     },
     "publishConfig": {
         "registry": "https://registry.npmjs.org"
diff --git a/registry.mjs b/registry.mjs
index 217ab19..ee8ad4b 100644
--- a/registry.mjs
+++ b/registry.mjs
@@ -13,39 +13,49 @@ export const REGISTRIES = {
 }
 
 /**
- *
- * Note that `registryLineNumber` is index + 1
- *
+ * Returns undefined when line does not contain registry, or registry as string
+ * @param {string} line
+ */
+function checkLine(line) {
+    let currLine = line.trim()
+    const keyName = 'registry'
+    if (!currLine.startsWith(keyName)) return
+    currLine = currLine.slice(keyName.length).trimStart()
+    if (!currLine.startsWith('=')) return
+    return currLine.slice(1).trimStart()
+}
+
+/**
  * @param {NodeJS.ReadableStream} stream
- * @returns {Promise<{registry:string,lines:string[],registryLineNumber:number}
- *                  |{registry:null,lines:string[],registryLineNumber:null}>}
+ * @returns {Promise<string|undefined>}
  * @see https://docs.npmjs.com/cli/configuring-npm/npmrc
- *
- * @example
- * const fileStream = fs.createReadStream(path)
- * findRegistryFromStream(fileStream)
  */
-export async function findRegistryFromStream(stream) {
+export async function getRegistryFromStream(stream) {
     const rl = readline.createInterface(stream)
-    /**
-     * @type {string[]}
-     */
-    const lines = []
-
-    for await (const entireLine of rl) {
-        lines.push(entireLine)
-
-        let currLine = entireLine.trim()
-        const keyName = 'registry'
-        if (!currLine.startsWith(keyName)) continue
-        currLine = currLine.slice(keyName.length).trimStart()
-        if (!currLine.startsWith('=')) continue
-        currLine = currLine.slice(1).trimStart()
+    for await (const line of rl) {
+        const r = checkLine(line)
+        if (r) return r
+    }
+}
 
-        // now that current line is the registry url
-        return { registry: currLine, lines, registryLineNumber: lines.length }
+/**
+ * Returns the proceed rc content
+ * @param {NodeJS.ReadableStream} stream
+ * @param {string} registryUrl
+ * @returns {Promise<string>}
+ */
+export async function setRegistryFromStream(stream, registryUrl) {
+    const rl = readline.createInterface(stream)
+    const lines = []
+    for await (const line of rl) {
+        const r = checkLine(line)
+        if (r) {
+            lines.push(`registry=${registryUrl}`)
+        } else {
+            lines.push(line)
+        }
     }
-    return { registry: null, registryLineNumber: null, lines }
+    return lines.join('\n')
 }
 
 /**
diff --git a/registry.test.mjs b/registry.test.mjs
index 3faf3e7..a6dc345 100644
--- a/registry.test.mjs
+++ b/registry.test.mjs
@@ -1,31 +1,28 @@
 import { test } from 'node:test'
 import * as assert from 'node:assert'
 import { Readable } from 'node:stream'
-import { findRegistryFromStream } from './registry.mjs'
+import { getRegistryFromStream } from './registry.mjs'
 
-test('test findRegistryFromStream()', async () => {
-    assert.deepStrictEqual(await findRegistryFromStream(Readable.from('')), {
-        lines: [],
-        registry: null,
-        registryLineNumber: null,
-    })
+test('test getRegistryFromStream()', async () => {
+    assert.deepStrictEqual(
+        await getRegistryFromStream(Readable.from('')),
+        undefined
+    )
 
-    const text2 = `registry=https://registry.npmmirror.com/`
+    assert.deepStrictEqual(
+        await getRegistryFromStream(
+            Readable.from(`registry=https://registry.npmmirror.com/`)
+        ),
+        'https://registry.npmmirror.com/'
+    )
 
-    assert.deepStrictEqual(await findRegistryFromStream(Readable.from(text2)), {
-        registry: 'https://registry.npmmirror.com/',
-        registryLineNumber: 1,
-        lines: [text2],
-    })
-
-    const text3 = `//registry.npmjs.org/:_authToken=npm_123456
+    assert.deepStrictEqual(
+        await getRegistryFromStream(
+            Readable.from(`//registry.npmjs.org/:_authToken=npm_123456
 
 # strict-ssl=false
-registry= https://registry.npmmirror.com/`
-
-    assert.deepStrictEqual(await findRegistryFromStream(Readable.from(text3)), {
-        registry: 'https://registry.npmmirror.com/',
-        registryLineNumber: 4,
-        lines: text3.split(/\n/g),
-    })
+registry= https://registry.npmmirror.com/`)
+        ),
+        'https://registry.npmmirror.com/'
+    )
 })
diff --git a/tty.mjs b/tty.mjs
deleted file mode 100644
index 1713243..0000000
--- a/tty.mjs
+++ /dev/null
@@ -1,82 +0,0 @@
-import { REGISTRIES } from './registry.mjs'
-
-/**
- * @param {string} str
- * @param {number} begin
- * @param {number} end
- */
-const color = (str, begin, end) => `\u001b[${begin}m${str}\u001b[${end}m`
-
-const c = {
-    /** @param {string} str*/
-    blue: (str) => color(str, 34, 39),
-    /** @param {string} str*/
-    red: (str) => color(str, 31, 39),
-    /** @param {string} str*/
-    green: (str) => color(str, 32, 39),
-    /** @param {string} str*/
-    yellow: (str) => color(str, 33, 39),
-    /** @param {string} str*/
-    magenta: (str) => color(str, 35, 39),
-    /** @param {string} str*/
-    cyan: (str) => color(str, 36, 39),
-    /** @param {string} str*/
-    gray: (str) => color(str, 90, 39),
-
-    /** @param {string} str*/
-    bold: (str) => color(str, 1, 22),
-    /** @param {string} str*/
-    italic: (str) => color(str, 3, 23),
-}
-
-export default c
-
-/**
- * @param {string} currentRegistryUrl
- * @param {Array<{name:string,url:string,timeSpent?:number|null}>} registriesInfo
- * @param {number=} timeoutLimit - milliseconds
- */
-export function printRegistries(
-    currentRegistryUrl,
-    registriesInfo = Object.entries(REGISTRIES).map(([name, url]) => ({
-        name,
-        url,
-    })),
-    timeoutLimit
-) {
-    const maxNameLength = Math.max(
-        ...registriesInfo.map(({ name }) => name.length)
-    )
-    /**
-     * @type {number=}
-     */
-    let maxUrlLength = undefined
-
-    for (let { name, url, timeSpent } of registriesInfo) {
-        if (timeoutLimit) {
-            // lazy compute
-            if (!maxUrlLength)
-                maxUrlLength = Math.max(
-                    ...registriesInfo.map(({ url }) => url.length)
-                )
-        }
-
-        let row = `${name.padEnd(maxNameLength)} → ${
-            maxUrlLength ? url.padEnd(maxUrlLength) : url
-        }`
-        if (url === currentRegistryUrl) row = c.blue(row)
-
-        if (timeoutLimit) {
-            if (!timeSpent) {
-                row += c.red(` (Error)`)
-            } else if (timeSpent >= timeoutLimit) {
-                row += c.red(` (>${(timeoutLimit / 1000).toFixed(1)}s)`)
-            } else if (timeSpent >= timeoutLimit / 2) {
-                row += c.yellow(` (${(timeSpent / 1000).toFixed(2)}s)`)
-            } else {
-                row += c.green(` (${(timeSpent / 1000).toFixed(2)}s)`)
-            }
-        }
-        console.log(row)
-    }
-}
diff --git a/utils.mjs b/utils.mjs
index f402982..cc455e6 100644
--- a/utils.mjs
+++ b/utils.mjs
@@ -1,4 +1,6 @@
 import { stat } from 'node:fs/promises'
+import { REGISTRIES } from './registry.mjs'
+
 /**
  * @param {string} filePath
  * @noexcept
@@ -7,3 +9,87 @@ export const isFile = async (filePath) =>
     await stat(filePath)
         .then((stat) => stat.isFile())
         .catch((_) => false)
+
+/**
+ * @param {string} str
+ * @param {number} begin
+ * @param {number} end
+ */
+const color = (str, begin, end) => `\u001b[${begin}m${str}\u001b[${end}m`
+
+/**
+ * Check out https://github.com/YieldRay/terminal-sequences/blob/main/sgr/style.ts
+ */
+const c = {
+    /** @param {string} str*/
+    blue: (str) => color(str, 34, 39),
+    /** @param {string} str*/
+    red: (str) => color(str, 31, 39),
+    /** @param {string} str*/
+    green: (str) => color(str, 32, 39),
+    /** @param {string} str*/
+    yellow: (str) => color(str, 33, 39),
+    /** @param {string} str*/
+    magenta: (str) => color(str, 35, 39),
+    /** @param {string} str*/
+    cyan: (str) => color(str, 36, 39),
+    /** @param {string} str*/
+    gray: (str) => color(str, 90, 39),
+
+    /** @param {string} str*/
+    bold: (str) => color(str, 1, 22),
+    /** @param {string} str*/
+    italic: (str) => color(str, 3, 23),
+}
+
+export default c
+
+/**
+ * @param {string} currentRegistryUrl
+ * @param {Array<{name:string,url:string,timeSpent?:number|null}>} registriesInfo
+ * @param {number=} timeoutLimit - milliseconds
+ */
+export function printRegistries(
+    currentRegistryUrl,
+    registriesInfo = Object.entries(REGISTRIES).map(([name, url]) => ({
+        name,
+        url,
+    })),
+    timeoutLimit
+) {
+    const maxNameLength = Math.max(
+        ...registriesInfo.map(({ name }) => name.length)
+    )
+    /**
+     * @type {number=}
+     */
+    let maxUrlLength = undefined
+
+    for (let { name, url, timeSpent } of registriesInfo) {
+        if (timeoutLimit) {
+            // lazy compute
+            if (!maxUrlLength)
+                maxUrlLength = Math.max(
+                    ...registriesInfo.map(({ url }) => url.length)
+                )
+        }
+
+        let row = `${name.padEnd(maxNameLength)} → ${
+            maxUrlLength ? url.padEnd(maxUrlLength) : url
+        }`
+        if (url === currentRegistryUrl) row = c.blue(row)
+
+        if (timeoutLimit) {
+            if (!timeSpent) {
+                row += c.red(` (Error)`)
+            } else if (timeSpent >= timeoutLimit) {
+                row += c.red(` (>${(timeoutLimit / 1000).toFixed(1)}s)`)
+            } else if (timeSpent >= timeoutLimit / 2) {
+                row += c.yellow(` (${(timeSpent / 1000).toFixed(2)}s)`)
+            } else {
+                row += c.green(` (${(timeSpent / 1000).toFixed(2)}s)`)
+            }
+        }
+        console.log(row)
+    }
+}