A similar solution to the one Louis suggested is to again use Regular expression search within Notepad++, with the search parameter:
And replace with:
The advantage/difference of this version over Louis' one is that it will also match first words like
Hyphen-ated where there are non alphanumeric characters.
This matches everything from the start of each line (the
^ symbol means start of line).
It finds at least one character (
.+? is non-greedy match one or more characters) stopping as soon as it finds a blank (
\s is blank/space).
It then carries on matching everything else in the line (
.* is match zero or more characters), up to the end of the line (
$ is end of line).
\1 will then only keep the section matched within the brackets, I.E. everything before the first space in the line.
N.B. make sure the
. matches newline checkbox is unticked, or you will only get the first word in the whole document.