Setting Up Your Environment

Prerequisites: Installing Julia

Editor

Visual Studio Code with the official Julia extension is the most popular setup: it gives autocompletion, inline results, a plot pane, a debugger, and a REPL connected to your editor (Shift + Enter runs the current line or selection).

Notebooks

Pluto.jl — a reactive notebook written in Julia: change a cell and every cell that depends on it updates automatically.
Jupyter — install the IJulia package to use Julia in Jupyter notebooks.

Running files

Save code in a file ending in .jl and run it from a terminal:

julia hello.jl
julia --startup-file=no hello.jl    # skip your personal startup file
julia -i hello.jl                   # run the file, then stay in the REPL

Revise.jl

Once you start writing larger programs, install Revise.jl: it reloads your code automatically when you save a file, so you don't have to restart Julia (and recompile) after every change. You'll learn to install packages in Level 2.

Formatting

JuliaFormatter.jl formats code consistently, and the VS Code extension can run it on save.