shopt -s extglob

TESTDIR=${TMPDIR:-/tmp}/eglob-test-$$
mkdir $TESTDIR
builtin cd $TESTDIR || { echo $0: cannot cd to $TESTDIR >&2 ; exit 1; }
rm -rf *

touch a ab ba

echo a*!(x)
echo a!(x)
echo a*?(x)
echo a?(x)

builtin cd /
rm -rf $TESTDIR