I knew about the possibility to get backup db using SQL server agent, but I was curious to know if we can have a backup script (like batch file) that just runs in windows and gets automatic backup according to the schedule that we define?

I think for the next part we can use windows task schedule (or crontab) for run the backup script job routinely, but the most important thing is to know: is it possible to login via SQL and backup the DB just using a batch scrip file (that there not be any need for SQL management studio completely and work completely independent)?  

If the answer is yes, please let me know that I have it, too. 

Maybe it seems to be a silly question, but I am not so experienced about that here.