parameter=abcdef
offset=2
noffset=-2
echo "parameter     '${parameter}'"
echo "varoffset2    '${parameter:${offset}}'"
echo "varoffset-2   '${parameter:${noffset}}'"
echo "literal '2'   '${parameter:2}'"
# This is not interpreted as ${VAR:POS{:LEN}},
# but as ${VAR:=WORD} - if VAR is unset or null, substitute WORD
echo "literal '-2'  '${parameter:-2}'"
echo "literal ' -2' '${parameter: -2}'"