grep patterns and matching options

1. grep with multiple pattern: -E, –extended-regexp: PATTERN is an extended regular expression

grep -a -E "apple|orange" file.txt

1. grep the binary file -a, –text: equivalent to –binary-files=text

grep -a  "apple" file.txt

1. -i , grep without fixed case

   grep -a -i "product_7" subeset_product_combined.txt