regex - line ends with operator

We would like to get the string that ends with the given search term. For this use $ operator - we place this operator at the end of search term.

Example 1:

$ grep 'sam$' names.txt
basam

Example 2:

$ grep '7$' /etc/login.defs 
ERASECHAR	0177
PASS_WARN_AGE	7

Example 3:

$ grep 'mail$' /etc/login.defs 
MAIL_DIR        /var/mail
#MAIL_FILE      .mail