1*f84460ddSJilles Tjoelker 2*f84460ddSJilles Tjoelker# \u without any digits at all remains invalid. 3*f84460ddSJilles Tjoelker# Our choice is a parse error. 4*f84460ddSJilles Tjoelker 5*f84460ddSJilles Tjoelkerv=$( (eval ": \$'\u'") 2>&1 >/dev/null) 6*f84460ddSJilles Tjoelker[ $? -ne 0 ] && [ -n "$v" ] 7