How to make grep stop at first match on a line?

Question

Well, I have a file test.txt

#test.txt
odsdsdoddf112 test1_for_grep
dad23392eeedJ test2 for grep
Hello World test
garbage

I want to extract strings which h

Answer 1

If we want to extract all meaningful input before garbage and actually stop on first match then -B NUM, --before-context=NUM option may be useful to "print NUM lines of leading context before matching lines".

Example:

grep --before-context=999999 "Hello World test"