linux grep different strings code example

Example 1: bash print lines that contain multiple specific words

# Basic syntax:
grep first_word input_file | grep second_word
# This finds all lines that contain the first_word and then pipes them
# to a second filter that looks for the second_word, resulting in all
# lines that contain both words. Simply add more pipes and greps to 
# return lines that meet other search criteria.

Example 2: grep more than one word

Just use one of following forms with grep or egrep commands :)
grep "PATTERN1\|PATTERN2" FILE
grep -E "PATTERN1|PATTERN2" FILE
grep -e PATTERN1 -e PATTERN2 FILE
egrep "PATTERN1|PATTERN2" FILE