what does $ in r mean code example

Example 1: meaning of %>% R

library(magrittr)
iris %>% head()
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa
3          4.7         3.2          1.3         0.2  setosa
4          4.6         3.1          1.5         0.2  setosa
5          5.0         3.6          1.4         0.2  setosa
6          5.4         3.9          1.7         0.4  setosa

Example 2: what does \r

///Before:

Console.WriteLine("Hello World\n"); 
//Does also count for "print" in Python or in C or in other programming languages

Output:
Hello World
           Hello World

///After:

Console.WriteLine("Hello World\n\r");
Output:
Hello World
Hello World