It's a unix system

Last login: Thu Nov 15 19:33:02 on ttys001
Erics-Mac-mini:~ eric$
Erics-Mac-mini:~ eric$ echo PATH$
PATH$
Erics-Mac-mini:~ eric$ ls
Applications	Downloads	Library		Music		Sites
Desktop		Dropbox		License.pdf	Pictures	luac.out
Documents	Google Drive	Movies		Public
Erics-Mac-mini:~ eric$ ~/.profile
-bash: /Users/eric/.profile: Permission denied
Erics-Mac-mini:~ eric$ adb
-bash: adb: command not found
Erics-Mac-mini:~ eric$ cd Applications
Erics-Mac-mini:Applications eric$ ls
FTL Faster Than Light.app
Erics-Mac-mini:Applications eric$