diff --git a/src/cli.ts b/src/cli.ts
index 21f7964..487d47e 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -1,13 +1,13 @@
 import * as path from 'path';
 import * as fs from 'fs';
 import * as os from 'os';
-import { spawnSync } from 'child_process';
 import { Command } from 'commander';
 import { getPlatformInfo } from './core/platform';
 import { getMatchingAsset } from './core/matcher';
 import { findBinary } from './core/finder';
 import { fetchLatestRelease, fetchLatestReleaseRaw, downloadAsset } from './core/downloader';
 import { extractAsset } from './core/extractor';
+import { installSystemPackage } from './core/installer';
 
 interface CliOptions {
   appName?: string;
@@ -58,31 +58,6 @@ function getInstallDir(installPath?: string): string {
   return '/usr/local/bin';
 }
 
-function installSystemPackage(downloadPath: string): void {
-  const fileName = path.basename(downloadPath).toLowerCase();
-
-  const command: { binary: string; args: string[] } | undefined = fileName.endsWith('.deb')
-    ? { binary: 'dpkg', args: ['-i', downloadPath] }
-    : fileName.endsWith('.pkg')
-      ? { binary: 'installer', args: ['-pkg', downloadPath, '-target', '/'] }
-      : fileName.endsWith('.rpm')
-        ? { binary: 'rpm', args: ['-i', downloadPath] }
-        : undefined;
-
-  if (!command) {
-    throw new Error(`Unsupported package type: ${fileName}`);
-  }
-
-  const isRoot = process.getuid && process.getuid() === 0;
-  const commandToRun = isRoot ? command.binary : 'sudo';
-  const argsToRun = isRoot ? command.args : [command.binary, ...command.args];
-
-  const result = spawnSync(commandToRun, argsToRun, { stdio: 'inherit' });
-  if (result.status !== 0) {
-    throw new Error(`Failed to install package using ${commandToRun} ${argsToRun.join(' ')}.`);
-  }
-}
-
 async function run() {
   let tempDir: string | undefined;
   const program = new Command();
diff --git a/src/core/installer.ts b/src/core/installer.ts
new file mode 100644
index 0000000..3fe28e1
--- /dev/null
+++ b/src/core/installer.ts
@@ -0,0 +1,27 @@
+import * as path from 'path';
+import { spawnSync } from 'child_process';
+
+export function installSystemPackage(downloadPath: string): void {
+  const fileName = path.basename(downloadPath).toLowerCase();
+
+  const command: { binary: string; args: string[] } | undefined = fileName.endsWith('.deb')
+    ? { binary: 'dpkg', args: ['-i', downloadPath] }
+    : fileName.endsWith('.pkg')
+      ? { binary: 'installer', args: ['-pkg', downloadPath, '-target', '/'] }
+      : fileName.endsWith('.rpm')
+        ? { binary: 'rpm', args: ['-i', downloadPath] }
+        : undefined;
+
+  if (!command) {
+    throw new Error(`Unsupported package type: ${fileName}`);
+  }
+
+  const isRoot = process.getuid && process.getuid() === 0;
+  const commandToRun = isRoot ? command.binary : 'sudo';
+  const argsToRun = isRoot ? command.args : [command.binary, ...command.args];
+
+  const result = spawnSync(commandToRun, argsToRun, { stdio: 'inherit' });
+  if (result.status !== 0) {
+    throw new Error(`Failed to install package using ${commandToRun} ${argsToRun.join(' ')}.`);
+  }
+}
diff --git a/src/index.ts b/src/index.ts
index ad86422..e338ec1 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -7,53 +7,35 @@ import { getPlatformInfo } from './core/platform';
 import { getMatchingAsset } from './core/matcher';
 import { findBinary } from './core/finder';
 import { fetchLatestRelease } from './core/downloader';
-
-function installSystemPackage(downloadPath: string): void {
-  const fileName = path.basename(downloadPath).toLowerCase();
-
-  const command: { binary: string; args: string[] } | undefined = fileName.endsWith('.deb')
-    ? { binary: 'dpkg', args: ['-i', downloadPath] }
-    : fileName.endsWith('.pkg')
-      ? { binary: 'installer', args: ['-pkg', downloadPath, '-target', '/'] }
-      : fileName.endsWith('.rpm')
-        ? { binary: 'rpm', args: ['-i', downloadPath] }
-        : undefined;
-
-  if (!command) {
-    throw new Error(`Unsupported package type: ${fileName}`);
-  }
-
-  const isRoot = process.getuid && process.getuid() === 0;
-  const commandToRun = isRoot ? command.binary : 'sudo';
-  const argsToRun = isRoot ? command.args : [command.binary, ...command.args];
-
-  const result = spawnSync(commandToRun, argsToRun, { stdio: 'inherit' });
-  if (result.status !== 0) {
-    throw new Error(`Failed to install package using ${commandToRun} ${argsToRun.join(' ')}.`);
-  }
-}
+import { installSystemPackage } from './core/installer';
 
 function findInstalledBinary(binaryName: string): string | undefined {
-  const isRegex = binaryName.startsWith('~');
-  if (!isRegex) {
-    const whichResult = spawnSync('which', [binaryName], { encoding: 'utf8' });
-    if (whichResult.status === 0) {
-      const resolvedPath = (whichResult.stdout || '').trim();
-      if (resolvedPath) {
-        return resolvedPath;
-      }
-    }
+  let pattern: RegExp;
+
+  if (!binaryName.startsWith('~')) {
+    pattern = new RegExp(`^${binaryName}$`, 'i');
+  } else {
+    pattern = new RegExp(binaryName.substring(1), 'i');
   }
 
-  const candidates = ['/usr/local/bin', '/usr/bin', '/opt/homebrew/bin', '/opt/local/bin'];
-  const pattern: string | RegExp = isRegex ? new RegExp(binaryName.substring(1), 'i') : binaryName;
-  for (const candidateDir of candidates) {
-    if (!fs.existsSync(candidateDir)) {
+  const dirs = [
+    '/usr/local/bin',
+    '/usr/local/sbin',
+    '/usr/bin',
+    '/usr/sbin',
+    '/bin',
+    '/sbin',
+    path.join(process.env.HOME || '/', 'bin'),
+    '/opt/homebrew/bin'
+  ];
+
+  for (const d of dirs) {
+    if (!fs.existsSync(d)) {
       continue;
     }
-    const candidatePath = findBinary(candidateDir, pattern, false, () => undefined);
-    if (candidatePath) {
-      return candidatePath;
+    const p = findBinary(d, pattern, false, () => undefined);
+    if (p) {
+      return p;
     }
   }