Is it possible to enable Code Folding in Xcode for Bash scripts?
I haven't found a way to enable code folding for bash script in Xcode.

But here is an alternative: UltraEdit.
UE allows code folding for bash scripts after tweaking a file.

In the example below i have added

/Open Fold Strings = "{" "if" "elif" "do"
/Close Fold Strings = "}" "elif" "fi" "done"
/Ignore Fold Strings = "echo"


to the file ~/Library/Application Support/UltraEdit/wordfiles/bash.uew

Depending on your needs you may add other strings of course.