How to grep a word inside xml files in a folder

I know I can use grep to find a word in all the files present in a folder like this

grep -rn core .

But my current directory has many sub-directories and I just want to search in all xml files present in the current directory and its all sub directories. How can I do that ?

I tried this

grep -rn core *.xml // Does not work

But it searches for xml files present in the current directory only. It does not do it recursively.

Answer

Try the –include option

grep -R --include="*.xml" "pattern" /path/to/dir

Reference: Grep Include Only *.txt File Pattern When Running Recursive Mode