sed notes

sed -ie 's/word1/word2/g' /testing

find word1 and replace it to word2 inside /testing file
-i option is used to edit in place on the file testing.

-e option indicates the expression/command to run, in this case s/.

Notes:
the / can be replace with anything as long no conflict with inside word
example

sed -ie 's:word1:word2:g' /testing