PATH vs current dir and dir sure to be not existing

[<tlaronde%kergis.com@localhost>]

POSIX mandates that an empty dir in the PATH env variable (i.e. an
initial or terminal colon, or an empty entry "...::...") be treated as
meaning the current working dir, allowing to try to execute the
searched utility there.

This does mean that one user setting a PATH with variables:

PATH="/bin:/usr/bin:$MYSCRIPTS:/usr/pkg/bin"

if MYSCRIPTS is not defined, will end up including the current working
dir in his PATH, while it was not the intention.

The general rule of safety is doing:

PATH="/bin:/usr/bin:${MYSCRIPTS:-/not/existing}:/usr/pkg/bin"

but is there a pathname that is guaranteed not to exist?

Or is using "/dev/null" the choice? Or defining a special file in /dev
that will always have permissions as 0000? (and then what name? and
that will log what tried to access it.)

-- 
        Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
                     http://www.kergis.com/
                    http://kertex.kergis.com/
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