Problem with BASH and [ ! -t 0 ] test.

[Chuck Swiger]

On Feb 18, 2009, at 12:29 PM, GESBBB wrote:
> I am a little confused. I believe the problem is with the "if [ ! -t  
> 0 ]" statement. I tried to redirect the error message; however, it  
> still appears in the email sent by CRON. I tried using this  
> statement instead: if ( ! tty -s &> /dev/null ) and "if ( ! tty -s )  
> &> /dev/null"; however, they also produce an error message although  
> the function does work correctly. Is this just something I should  
> just ignore, or is there a way to stop the message from being sent  
> in the CRON report?

For Bourne shell, classic /bin/sh, and related shells (zsh, ksh), you  
can use something like:

case $- in
     *i*)
     # do stuff for an interactive shell
     echo "interactive"
     ;;
     *)
     # not interactive
     echo "not interactive"
     ;;
esac

Regards,
-- 
-Chuck