What does . & .. in a directory represent
 

Hi

Command ls -a out put shows two hidden directories . and .. I can see the same in all the directories. Plz can anybody tell me what they represent.
Also using cd command i cant enter to these directories....

. is the directory you are in i.e. the current directory.

.. is the parent directory, so if you're in /home/soji and you do ls .., that will show the contents of /home.

Any directory/files whose name starts with "." means its a hidden directory/files. I guess these has the informations about the current directory.

Similar "-" represents the previous directory. So if you do a "cd - " it will jump to the previous directory. Its like a back button in the explorer

Thank you so much ...