2.3 Using R
R is very simple. There is a console where you type commands and get responses. Like the classic command-line interfaces you see when the stereotypical nerd has to hack into the FBI database, you type commands, one at a time into the console, R processes it, and then produces a response if appropriate. For example, if you type
2 + 2 into the R console and hit enter, you'll get
Writing commands out one at a time can be quite time-consuming if you want to make changes however. So we use scripts to store multiple lines of code that can then be run altogether. When you execute a script, each line gets passed one by one to the console and executed. For example, I might make a script with this code:
variable1 <- 2 + 2 variable1 / 10
##  0.4
So when I run the script, it will run the first line, then the second without me having to type anything else in.