<p dir="auto">When running the <code class="notranslate">services/isolate.dart</code> sample app on a Nexus 5X and clicking <em>Start</em> button it immediately crashes with the following output:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="~/projects/flutter/examples/layers$ flutter run -t services/isolate.dart 
Running 'pub get' in layers...                       6.2s
Building APK in debug mode (android-arm)...              
Warning: signing the APK using the debug keystore.
Built build/app.apk (8.7MB).
Running services/isolate.dart on Nexus 5X...
--------- beginning of main
Observatory listening on http://127.0.0.1:8102
Diagnostic server listening on http://127.0.0.1:8103
Application running.
Connected to view '_flutterView/0xf48196c0'.
Type &quot;h&quot; or F1 for help, &quot;r&quot; or F5 to restart the app, and &quot;q&quot;, F10, or ctrl-c to quit.
Type &quot;w&quot; to print the widget hierarchy of the app, and &quot;t&quot; for the render tree.
E/DartVM  : ../../dart/runtime/vm/object.h: 5455: error: Handle check failed: saw UnhandledException expected Instance
E/DartVM  : Dumping native stack trace for thread 3010
E/DartVM  :   [0xdae75f5d] Unknown symbol
E/DartVM  : -- End of DumpStackTrace
--------- beginning of crash
W/ActivityManager:   Force finishing activity io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity
W/ActivityManager:   Force finishing activity io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity
W/ActivityManager: Duplicate finish request for ActivityRecord{7d0b96c u0 io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity t59 f}
Application finished."><pre class="notranslate"><code class="notranslate">~/projects/flutter/examples/layers$ flutter run -t services/isolate.dart 
Running 'pub get' in layers...                       6.2s
Building APK in debug mode (android-arm)...              
Warning: signing the APK using the debug keystore.
Built build/app.apk (8.7MB).
Running services/isolate.dart on Nexus 5X...
--------- beginning of main
Observatory listening on http://127.0.0.1:8102
Diagnostic server listening on http://127.0.0.1:8103
Application running.
Connected to view '_flutterView/0xf48196c0'.
Type "h" or F1 for help, "r" or F5 to restart the app, and "q", F10, or ctrl-c to quit.
Type "w" to print the widget hierarchy of the app, and "t" for the render tree.
E/DartVM  : ../../dart/runtime/vm/object.h: 5455: error: Handle check failed: saw UnhandledException expected Instance
E/DartVM  : Dumping native stack trace for thread 3010
E/DartVM  :   [0xdae75f5d] Unknown symbol
E/DartVM  : -- End of DumpStackTrace
--------- beginning of crash
W/ActivityManager:   Force finishing activity io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity
W/ActivityManager:   Force finishing activity io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity
W/ActivityManager: Duplicate finish request for ActivityRecord{7d0b96c u0 io.flutter.examples.Layers/org.domokit.sky.shell.SkyActivity t59 f}
Application finished.
</code></pre></div>
<p dir="auto">Just in case, here is my <code class="notranslate">flutter doctor</code> output:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="$ flutter doctor
[✓] Flutter (on Linux, channel master)
    • Flutter at /home/lex/projects/flutter
    • Framework revision b298bdc8c4 (26 hours ago), 2016-09-09 16:55:55
    • Engine revision a55fa1efb9
    • Tools Dart version 1.20.0-dev.1.0

[✓] Android toolchain - develop for Android devices (Android SDK 19.1.0)
    • Android SDK at /home/lex/projects/Android/Sdk
    • Platform android-19, build-tools 19.1.0
    • OpenJDK Runtime Environment (build 1.8.0_91-8u91-b14-3ubuntu1~16.04.1-b14)

[✓] Atom - a lightweight development environment for Flutter
    • flutter plugin version 0.2.4
    • dartlang plugin version 0.6.37

[✓] Connected devices
    • Nexus 5X • 00dd4847616ed5cd • android-arm"><pre class="notranslate"><code class="notranslate">$ flutter doctor
[✓] Flutter (on Linux, channel master)
    • Flutter at /home/lex/projects/flutter
    • Framework revision b298bdc8c4 (26 hours ago), 2016-09-09 16:55:55
    • Engine revision a55fa1efb9
    • Tools Dart version 1.20.0-dev.1.0

[✓] Android toolchain - develop for Android devices (Android SDK 19.1.0)
    • Android SDK at /home/lex/projects/Android/Sdk
    • Platform android-19, build-tools 19.1.0
    • OpenJDK Runtime Environment (build 1.8.0_91-8u91-b14-3ubuntu1~16.04.1-b14)

[✓] Atom - a lightweight development environment for Flutter
    • flutter plugin version 0.2.4
    • dartlang plugin version 0.6.37

[✓] Connected devices
    • Nexus 5X • 00dd4847616ed5cd • android-arm
</code></pre></div>
<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">I am new to flutter, was just trying to install it on my machine(ubuntu 17.10 , 64-bit). After setting PATH variable as mentioned <a href="https://flutter.io/setup-linux/#clone-the-repo" rel="nofollow">here</a>, I tried to run command " flutter doctor". And got an error</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="line 33 : sed : command not found"><pre class="notranslate"><code class="notranslate">line 33 : sed : command not found
</code></pre></div>
<p dir="auto">I opened that shell script <a href="https://github.com/flutter/flutter/blob/2171fcb882a63e8ea2408dec4771ce0611621739/bin/flutter#L33">here</a> , found that this <code class="notranslate">'s,^/+,/,'</code> to be written in Double quotation marks. And changed it to Single Quotation Marks. And everything Works Fine.</p>
<h2 dir="auto">My Questions</h2>
<ol dir="auto">
<li>
<p dir="auto">Will Changing Quotation marks make any difference? (I know nothing about shell scripting and I think answer would be not as it works correctly )</p>
</li>
<li>
<p dir="auto">And if there is no variable there why are we using double quotes as it makes trouble to some of us, maybe. (As mentioned <a href="https://stackoverflow.com/a/6697845/7910735" rel="nofollow">here)</a></p>
</li>
<li>
<p dir="auto">If we are going to change it to Single Quotaion marks, Can I create PR for it?</p>
</li>
</ol>
<h2 dir="auto">Flutter Doctor</h2>
<p dir="auto">Everything works fine after changes.</p>