#!/bin/bash
s='<User id="10338" directoryId="1" sometext txt text test/>
<User id="10359" directoryId="100" some more text text text/>
<User id="103599" directoryId="100" some more text text text/>
<User id="10438" directoryId="1" sometext txt text test/>'
sed -e '/directoryId="1"/b' -e '/<User id="/d' <<< "$s"
IyEvYmluL2Jhc2gKcz0nPFVzZXIgaWQ9IjEwMzM4IiBkaXJlY3RvcnlJZD0iMSIgc29tZXRleHQgdHh0IHRleHQgdGVzdC8+CjxVc2VyIGlkPSIxMDM1OSIgZGlyZWN0b3J5SWQ9IjEwMCIgc29tZSBtb3JlIHRleHQgdGV4dCB0ZXh0Lz4KPFVzZXIgaWQ9IjEwMzU5OSIgZGlyZWN0b3J5SWQ9IjEwMCIgc29tZSBtb3JlIHRleHQgdGV4dCB0ZXh0Lz4KPFVzZXIgaWQ9IjEwNDM4IiBkaXJlY3RvcnlJZD0iMSIgc29tZXRleHQgdHh0IHRleHQgdGVzdC8+JwpzZWQgLWUgJy9kaXJlY3RvcnlJZD0iMSIvYicgLWUgJy88VXNlciBpZD0iL2QnIDw8PCAiJHMi