1 files changed, 19 insertions, 0 deletions
diff --git a/deps/npm/lib/utils/is-hashbang-file.js b/deps/npm/lib/utils/is-hashbang-file.js
new file mode 100644
index 0000000000..f1677381fa
--- /dev/null
+++ b/deps/npm/lib/utils/is-hashbang-file.js
@@ -0,0 +1,19 @@
+'use strict'
+const Bluebird = require('bluebird')
+const fs = require('graceful-fs')
+const open = Bluebird.promisify(fs.open)
+const close = Bluebird.promisify(fs.close)
+
+module.exports = isHashbangFile
+
+function isHashbangFile (file) {
+  return open(file, 'r').then((fileHandle) => {
+    return new Bluebird((resolve, reject) => {
+      fs.read(fileHandle, new Buffer(new Array(2)), 0, 2, 0, function (err, bytesRead, buffer) {
+        close(fileHandle).then(() => {
+          resolve(!err && buffer.toString() === '#!')
+        }).catch(reject)
+      })
+    })
+  })
+}