Symbols

.    =   Current (working) directory.

. .    =  Parent directory; the directory directly above the current directory.

~(tilde)     =   User's home directory (Bash and Bash Shells).

< (left angle bracket )
Left angle bracket is used to redirect the standard input of a command from a file instead of from the keyboard.

  ;(semicolon)
Also known as the command separator, it allows you to enter multiple commands on a single command line.