Grep

Invert match on multiple words

echo "hello world" | grep -vE 'hello|foo'  #
echo "only bar" | grep -vE 'hello|foo'  # only bar

Basics

Show the filename containing pattern

grep -l 'pattern' file.txt

Show the filename and line

grep -Hn 'pattern' file.txt

Only first pattern

grep -m 1 'pattern' file.txt

Invert match

grep -v -E 'dont_want_that_pattern|neither_this' file.txt