if [ $?=0 ] ; then
echo '[ $?=0 ] is ok'
else
echo '[ $?=0 ] is not ok'
fi
echo '[ $?=0 ] is ok'
else
echo '[ $?=0 ] is not ok'
fi
if [ $? = 0 ] ; then
echo '[ $? = 0 ] is ok'
else
echo '[ $? = 0 ] is not ok'
fi
if [[ $? = 0 ]] ; then
echo '[[ $? = 0 ]] is ok'
else
echo '[[ $? = 0 ]] is not ok'
fi
if [[ $?=0 ]] ; then
echo '[[ $?=0 ]] is ok'
else
echo '[[ $?=0 ]] is not ok'
fi