Not Sure how to do this. Some combo of awk and sed perhaps. If String in File1 match String in file2 then append file2
File1.txt
BullTerrier
Boxer
Bulldog
File2.txt
<Defined info="AllAnimals" group="Adoptions" setting="animals">
<SomeID ="NumbersRepresentingDogName">
<for>
<add dog="BullTerrier"/>
</for>
</SomeID>
<SomeID ="NumbersRepresentingDogName">
<for>
<each1="adoption" bool="value"/>
<allocate="Boxer" database="databasename"/>
<add dog="Boxer"/>
</for>
</SomeID>
<SomeID ="NumbersRepresentingDogName">
<for>
<add dog="MadDog"/>
</for>
</SomeID>
</DefinedInfo>
AFTER RESULTS
<Defined info="AllAnimals" group="Adoptions" setting="animals">
<SomeID ="NumbersRepresentingDogName">
<for>
<add dog="--Ok to REMOVE BullTerrier"/>
</for>
</SomeID>
<SomeID ="NumbersRepresentingDogName">
<for>
<each1="adoption" bool="value"/>
<allocate="Boxer" database="databasename"/>
<add dog="--Ok to REMOVE Boxer"/>
</for>
</SomeID>
<SomeID ="NumbersRepresentingDogName">
<for>
<add dog="MadDog"/>
</for>
</SomeID>
</DefinedInfo>