sed replace every string in file code example

Example 1: sed replace in file

sed -i 's/foo/bar/g' hello.txt

Example 2: replace using sed

#on my mac
sed -i -e 's/old-text/new-text/g' text.txt

Example 3: sed replace from match

Just use a similar example with using ".*" regex with sed as following:
sed 's/match_pattern.*/replacement_of_match_and_rest_of_line/' file.txt