Grep Search For Multiple Strings

To search for multiple strings/patterns at once in grep we can do it by following ways -

Option 1

Using OR Operator |

$ echo -e "Hi\nThere\nHumans" | grep "Hi\|Humans"
Hi
Humans

Note: When using this approach, we need to escape | operator using backslash \.

Option 2

Using Extended Regular Expressions option -E

$ echo -e "Hi\nThere\nHumans" | grep -E "Hi|Humans"
Hi
Humans

Note: We don't have to escape | using -E option.

Source: Linuxize