Delete everything until substring match in vim

In vim, running this will delete everything before SUBSTR.

%s/^.*\(SUBSTR\)/\1/

Explained:

1. %s runs the substitute command
2. ^ matches start of the line
3. .* matches anything
4. \(SUBSTR\) matches literal “SUBSTR” and the parentheses around it captures the match
5. \1 replaces everything matched before with the captured match (in this case, SUBSTR)