Inability to run flutter upgrade via the terminal - flutter

I am new to mobile app development and I started using flutter but of late I have been trying to upgrade my verison of flutter via the terminal but it's not working.And the image below is what it does
A screenshot of my problem

Related

Problem in building and running flutter app

After some months of stop I'm trying to launch again an old flutter app, but idk I have a lot of problems. I had to install again flutter on the pc.
This is the error:

How to deploy flutter example for the web?

https://pub.dev/packages/flutter_tex/example (want to run this code for Flutter Web)
Goal: Deploy flutter example on a simple web page for checking latex code output
Expected result: Simple web page where you type Latex on the left and it shows you rendered equations on the right
My experience: 1 day
Current installation: Flutter, Dart, Android Studio, Dart -> Able to "create new Flutter project"
What I have tried: Opened a new flutter project - pasted code in main.dart - did not work (no device device - need virtual device for web deployment?)
In order to run your Flutter project on the web, you must ensure that you have the latest version of Flutter (currently I am running v2.0.2). If you don't have the latest version, just run flutter upgrade in the terminal.
Secondly, you need to check whether the package that you are using also supports the web platform. You can check it by going into the "Scores" tab in the package.
Then, all you have to do is to run the command:
flutter run -d chrome
This will launch the flutter app in the Google chrome browser.

Stuck at Syncing files to device Chrome when trying to run a web project

I'm stuck at Syncing files to device Chrome when running the project, the same result from vscode terminal and command prompt, I only get a white screen on a google window and it doesn't seem to be in progress anymore, the steps that I made to create the project are :
flutter channel master
flutter upgrade
flutter config --enable-web
flutter create webapp
cd webapp
flutter run
I tried to check the console with F12 on the browser but it is empty.
I can run the project only in the release mode with flutter run --release, but it so exhausting to test on this mode seen that the hot reload takes so much time.
It is recommended to use beta channel for web support in flutter.
flutter channel beta

How to fix unable to run Flutter app from VSCode

I was using VSCode and Flutter without any problem in my Ubuntu machine.
Recently, I installed Mircosoft .Net core in my machine.
Later when I try to run a Flutter application by pressing F5, it is trying to download C#.
I'm unable to run Flutter application from VSCode, where as I can run the app from console using the flutter run command.
Guess this is a bug in VSCode. It works after downloading, C# package. It is kind of high-volume btw.

How to use the official Flutter gallery

Im totally new to flutter, and would like to try out the official examples gallery: https://github.com/flutter/flutter/tree/master/examples/flutter_gallery
I´ve installed Android studio and have the emulator running, which works great when i start the demo app from VS code.
Problem is, how do i fetch the gallery app, and load it onto the virtual device? The simple guide says I should run these two commands:
flutter packages get
flutter run --release
This does not work, as the terminal throws this error: "Release mode is not supported for emulators." If I instead run
flutter run --debug
it loads up the "You have pushed the button x this many times" standard demo app. And i really cant see how these two commands tells the terminal to get the flutter gallery.
I´ve also tried to change the flutter channel to dev, but this dosent help.
Flutter doctor says everything is OK.
So how do I you try out the official flutter gallery app?
You need to switch to the project directory of the gallery app first
cd your_flutter_install_dir/examples/flutter_gallery
flutter packages get
flutter run
If you have a real device connected (and the emulator closed) you can also use flutter run release