How to replace all/first occurrence of TEST with TEST2 in a file?

Question

linux

You need to do the following using any grep, sed, awk utility :

Replace all/first occurrence(s) of TEST with TEST2 in the test.txt file. Output a line from the file only if the searched substring matches \s+SOMETEXT\s+.

Tell me where to dig and how to do it?

Thank you!

Answer 1

Tell me where to dig and how to do it?

Read manuals. This is the simplest thing that can be done with these utilities.