Running scripts

## Running a script with and without echo
source("source-echo-demo.R")
Hello world!
[1] 1
[1] 2
source("source-echo-demo.R",echo=TRUE)
> cat("Hello world!\n")
Hello world!

> a <- 1

> b <- 2

> a
[1] 1

> print(a)
[1] 1

> b
[1] 2

> show(b)
[1] 2