How to count nbr of linesin all the files of a directory?

find . -type f | xargs wc -l

find . -type f | grep .py$ | xargs wc -l

find . -name "*.py" | xargs wc -l

How to count occurrences of a word in all the files of a directory?

grep -roh {WORD} {DIR_PATH} | wc -w