env: bash\r: No such file or directory

>vim gradlew
:set fileformat=unix
:wq
>./gradlew clean build

The error message suggests that the script you're invoking has embedded \r characters, which in turn suggests that it has Windows-style \r\n line endings instead of the \n-only line endings bash expects.

As a quick fix, you can remove the \r chars. as follows:

sed $'s/\r$//' ./install.sh > ./install.Unix.sh

^{Note: The $'...' string is an ANSI-C quoted string supported in bash, ksh, and zsh. It is used to ensure that the \r expands to an actual CR character before sed sees the script, because not all sed implementations themselves support \r as an escape sequence.}

and then run

./install.Unix.sh --clang-completer

However, the larger question is why you've ended up with \r\n-style files - most likely, other files are affected, too.

Perhaps you're running Git on Windows, where a typical configuration is to convert Unix-style \n-only line breaks to Windows-style \r\n line breaks on checking files out and re-converting to \n-only line breaks on committing.

While this makes sense for development on Windows, it gets in the way of installation scenarios like these.

To make Git check out files with Unix-style file endings on Windows - at least temporarily - use:

git config --global core.autocrlf false

Then run your installation commands involving git clone again.

To restore Git's behavior later, run git config --global core.autocrlf true.