Did you read the article I mentioned? If
/usr/bin/env is not able to be executed from R, then there is some difference in the two environments that you need to nail down.
Since the terminal is not working, you could always explore the environment through R with things like:
system("ls -lha /usr/bin/env")
Then determining the differences (and where they are originating from) will amount to comparing the two environments (comparing environment variables is a good place to start) and tracking down the startup differences (i.e. by looking at files like
Another important factor - are all users experiencing this issue or is it only your user? If only one user, I would focus on user-specific bash / R profiles. If system-wide, then you would probably be looking at system configuration and system startup files.