library(JuliaCall)

julia_setup()

Julia version 1.0.0 at location /Applications/Julia-1.0.app/Contents/Resources/julia/bin will be used.
Loading setup script for JuliaCall...
Finish loading setup script for JuliaCall.

julia_console()

It seems that you are not in the terminal. A simple julia console will be started.
Type exit and then enter to exit.

julia> sqrt(2)

1.4142135623730951

julia> exit

Exiting julia console.

julia_library("Plots")

julia_command("gr()")

Plots.GRBackend()

julia_command("Plots.plot(Plots.fakedata(50,5),w=3)")