在shell脚本中使用sed命令在XML文件中添加XML元素

我有xml文件

<Students>
    <student>
        <name>john</>
        <id>123</id>
    </student>
    <student>
        <name>mike</name>
        <id>234</id>
    </student>
</Students>

我想添加新元素作为

<student>
        <name>NewName</name>
        <id>NewID</id>
    </student>

所以我的新xml文件将是

<Students>
    <student>
        <name>john</>
        <id>123</id>
    </student>
    <student>
        <name>mike</name>
        <id>234</id>
    </student>
    <student>
        <name>NewName</name>
        <id>NewID</id>
    </student>
</Students>

为此,我编写了shell脚本

#! /bin/bash

CONTENT="<student>
            <name>NewName</name>
            <id>NewID</id>
        </student>"

#sed -i.bak '/</Students>/ i  "$CONTENT" /root/1.xml
sed -i.bak '/</Students>/ i '$CONTENT'/' /root/1.xml

我收到错误了

sed: can't read <name>NewName</name>: No such file or directory
sed: can't read <id>NewID</id>: No such file or directory
sed: can't read </student>: No such file or directory

并且在xml文件中,只有< student>被添加.
其余元素未添加.
有谁知道为什么这个错误？