Re: exec command and error checking

[Guido Berhoerster <gber@opensuse.org>]

* Seb <sbb@tuxfamily.org> [2014-01-28 14:41]:
> Le Tue, 28 Jan 2014 18:16:23 +0600
> > So, I cannot test this operation without using $?
> 
> You can use the file tests:
> 
>  if [ -f no_such_file -a -r no_such_file ]; then
>    exec 9<no_such_file
>  else
>    echo TEST
>  fi
> 
> or a subshell:
> 
>  if ( exec 9<no_such_file ) 2>/dev/null; then
>    exec 9<no_such_file
>  else
>    echo TEST
>  fi

That's generally a bad idea since it is racy, if no_such_file is
removeded in between the test and actual exec your script will
still exit. Also, do no use test -a if you care about portability,
it's an XSI extension and marked obsolescent.
-- 
Guido Berhoerster