How to view RAM status information

How to get a list of files starting with the F letter

Suppose your current working directory is your home directory. 

How could you run the script 'demo.sh' that  is located in your home directory?  

Find three correct answers.

In user`s home directory is folder 'photo dir'

Which of the three method will copy the directory named "photo dir" recursively from the user`s home directory to /backups?

What is the output of:

In the script shown below

'greeting' is:

For example you in home directory and in this directory is some files including '.html' files.

How could you get a list of all '.html' files in current directory?

What protocols are used at 4 levels of the OSI model ?

Compare protocol and port:

What network device select the best path to route a message, based on the destination address of the packet ?