Hi beginner_99,
Note that the command:

Code:

grep -Fvf file2 file1

doesn't just remove the strings found in file2 from file1; it removes every line from file1 that contains any string found in file2.

And, assuming that the strings contained in file2 only consist of characters that are not "special" in a regular expression (RE), the code suggested by itkamaraj will not only remove the strings Happy and Hi from file1, it will also remove the string HHappyi (by removing Happy in the 1st invocation of sed and by removing the remaining Hi in the 2nd invocation of sed after removing Happy from HHappyi in the 1st invocation of sed).

The awk script suggested by RudiC will not only remove the strings Happy and Hi, but will also either remove the string HHappyi as in itkamaraj's sed script OR the strings HHiappy, HaHippy, HapHipy, and HappHiy depending on which of the two possible random orders awk uses to process the two lines found in file2 (there are 2**(N-1) possible random orders to process the N lines in file2 for the more general case).

If the strings you are processing might contain characters that are "special" in a regex used by awk or sed, you need to use awk instead of sed and use match() instead of sub() to find the matching strings or preprocess the REs in file2 to escape "special" characters.

If you want to remove all remaining matching strings after removing strings on the first pass, you'll need to use awk or sed commands to delete matched strings in a loop until no more matches are found.

Knowing these options, can you tell us if any of these issue matter with the real data you will be processing? And, if so, do you need help in figuring out how to make the needed changes to the suggestions you have received so far?