[Help-bash] Prevent file descriptor inheritance

[R. Diez]

Hi all:

Is there any way to prevent file descriptor inheritance? I mean the 
"close on exec" flag O_CLOEXEC or FD_CLOEXEC.

I wonder about the security implications. If a shell script opens a 
"secret" file, and runs an external command, that command will have 
direct access to the file.

Thanks in advance,
  rdiez