如何将字符串中相同模式依次替换为指定值生成BBcode彩色线条

[COLOR="#08070D"]_[COLOR="#100F1A"]_[COLOR="#191627"]_[COLOR="#211E34"]_[COLOR="#292541"]_[COLOR="#312D4E"]_[COLOR="#39345B"]_[COLOR="#413C68"]_[COLOR="#4A4375"]_[COLOR="#524A82"]_[COLOR="#5A528E"]_[COLOR="#62599B"]_[COLOR="#6C64A6"]_[COLOR="#7971AE"]_[COLOR="#827BB3"]_[COLOR="#8C85B9"]_[COLOR="#958FBF"]_[COLOR="#9F99C4"]_[COLOR="#A9A3CA"]_[COLOR="#B2AED0"]_[COLOR="#BCB8D6"]_[COLOR="#C5C2DC"]_[COLOR="#CFCCE2"]_[COLOR="#D9D6E8"]_[COLOR="#E2E0ED"]__[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]_[/color]

直接复制上述内容粘贴到支持BBCode语法的论坛，即可生成对应渐变彩色线条。

内容的提问来源于stack exchange，提问作者DelRey