Which of the following commands will output all of the lines that contain either the string Fred or fred? (Choose TWO correct answers.)

`grep -v fred data_file` uses the invert flag, which outputs lines that do NOT contain `fred`, and is also case-sensitive so it would miss `Fred`.

`grep '[f]red' data_file` only matches lowercase `fred`; the bracket class `[f]` is equivalent to just `f` and does not include `F`.

`egrep fred data_file` performs a case-sensitive match on the exact string `fred` and will not match `Fred`.

The pattern `[Ff]red` uses a bracket expression (character class) that matches either `F` or `f` followed by `red`, correctly matching both `Fred` and `fred`.

The `-i` flag makes `grep` case-insensitive, so `grep -i fred data_file` matches `fred`, `Fred`, `FRED`, and any other case variant.