How to trim text on each line, starting with the first space

Question

Windows 10, Emacs 25.1

Suppose I has text:

Advertisment    d184f52a-14d7-dddddddddd

ZAnelik 1c970d12-6c67-44e1-cccccccccccc

Avers   b0f0dd6b-a43f-4e40-b0ebbbbbbbbb

BAVERS_MIGOM_OLD    473aaaaaaaaaaa5a-b6df-d5d38327e4ed

I need to extract text in the first column. So result must be

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ZAnelik

Avers

BAVERS_MIGOM_OLD

How I can do this?

Answer 1

You can use C-M-% (query-replace-regexp) to delete text matching the pattern " .*$". i.e., everything, starting with whitespace, up to the end of the line.