1. There are three types of permisions in files and folders in unix
   1. Read (r)
   2. Write (w)
   3. Execute (x)
2. And, there is a clasificacion of users called UGO (explained bellow):
3. U ~> User (usually, you)

When applications are running in production, they become black boxes that need to be traced and monitored. One of the simplest, yet main, ways to do so is logging. Logging allows us - at the time we develop our software - to instruct the program to emit information while the system is running that will be useful for us and our sysadmins.