If I run this bash command and prefix the statement, so that the variable fruit should exist, but only for the duration of this command:$ fruit=apple echo $fruit$The result is an empty line. why?To quote a comment from wildcard on this question:parameter expansion is done by the shell, and the fruit variable is  not a shell variable; it's only an environment variable within the  environment of the echo commandAn environment variable is still a variable, so surely this should still be available to the echo command?
Why doesn't bash expand this variable when I prefix a command with a one time variable assignment
bash;variable