grep: match all characters up to (not including) first blank space

Question

I have a text file that has the following format:

characters(that I want to keep) (space) characters(that I want to remove)

So for example:

Answer 1

You are putting quantifier * at the wrong place.

Try instead this: -

grep '^[^\s]*' text1.txt > text2.txt

or, even better: -

grep '^\S*' text1.txt > text2.txt  

\S means match non-whitespace character. And anchor ^ is used to match at the beginning of the line.