How to delete everything up to a certain word in a file?

Question

linux

Hello!
There is a file with content, for example:
For is me my dir ....
Test me file remove gants
How to remove everything in it, leaving only the word gants Of
course, I would like it to be idempotent,
Using or lineinfile, replace.
Can't find regex regex.
Tell me, thanks

Answer 1

buff=$(grep -o "gants" filename)&&echo $buff > fulename