Copy file from another linux box through scp.

Sometimes you might need to access another Linux terminal for copying the file. Here is the situation.
You are on logged in a Linux box lets say A. And you want to copy a file from another Linux box X.X.X.X. The file is placed at /tmp directory of X.X.X.X at the source and you want to copy at /opt (your destination)

To do so we use scp
So it works like that

scp username@X.X.X.X:/tmp/fileToCopy  /opt/MyDestination