xcrun: error: active developer path ("/Applications/Xcode.app/Contents/Developer") does not exist

I tried that and it didn't work but I found the answer. I just had to reset the developer's path:

$ sudo xcode-select --reset

Now everything is normal

Mostly this error occurs when you have installed a newer version of xcode. And the command line tools are yet to be initialized.

To resolve this: Go under Xcode Preferences > Locations (tab) > And the bottom options is Command Line Tools. Please select the Xcode version for tools.

Example (For Xcode 10.0 (10A255) ): Go under Xcode Preferences > Locations (tab) > And the bottom options is Command Line Tools. Select Xcode 10.0 (10A255).

For more details please see the attached image. Hope it helps.

-- Thanks