$ printf 'a[]b[c]d[ef][g[h]i\n' | sed 's/\[[^][]*]/-/g'
    a-b-d-[g-i
    $ ed
    a
    a[]b[c]d[ef][g[h]i
    .
    s/\[[^][]*]/-/g
    p
    a-b-d-[g-i
    q
    ?
    q
    $