I'm aware than whenever I want to filter columns or... basically anything in a SQL query, i can use something like
Select * from table1 where name1 like "Mr.%"
You can do it with grep easily:
For a file:
grep '^Mr\.' myfile.txt
For command output:
my-command-with-output | grep '^Mr\.'
EDIT: Adding an example with your example text file string:
grep '^1' myfile.txt
The example above will find any lines with starting with the number 1.