I want to search for:
From start of the line, any number of white spaces followed by any number of digits NOT followed by a dot.
And replace it with all that was searched and a dot. This is just to introduce a dot in a simple numbered list when forgotten.
So, I went:
:%s/^\(\s*\d\+\)\.\@!/\1\.
This breaks down if there is a two digit number with a dot following it.
For example:
This
1 Some text
becomes this1. Some text
as expected.But, this
10. Some text
becomes1.0. Some text
instead staying unchanged.