Unix grep command to match exact string

Sometimes there is a requirement of matching exact word using grep command for this grep function has one optional parameter and other wildcards to make sure correct word/string is picked.

eg : Let's say we have a file with names Jack and Jacky if we use :

$ cat names.txt |grep Jack

Jack

Jacky

Output would be both to avoid this and only output Jack we can use below 3 methods:

1: -w option

$ cat names.txt | grep -w Jack

Jack

2 : \b characters

$ cat names.txt |grep "\bJack\b"

Jack

3: \< characters

$ cat names.txt |grep "\<Jack\>"

Jack