Book Image

Getting Started with Julia

By : Ivo Balbaert
Book Image

Getting Started with Julia

By: Ivo Balbaert

Overview of this book

Table of Contents (19 chapters)
Getting Started with Julia
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
The Rationale for Julia
Index

Startup options and Julia scripts


Without any options, the julia command starts up the REPL environment. A useful option to check your environment is julia –v. This shows Julia's version, for example, julia-version 0.3.2+2. (The versioninfo()function in REPL is more detailed, the VERSION constant gives you only the version number: v"0.3.2+2"). An option that lets you evaluate expressions on the command line itself is –e, for example:

  julia -e 'a = 6 * 7;
  println(a)'

The preceding commands print out 42 (on Windows, use " instead of the ' character).

Some other options useful for parallel processing will be discussed in Chapter 9, Running External Programs. Type julia –h for a list of all options.

A script.jl file with Julia source code can be started from the command line with the following command:

julia script.jl arg1 arg2 arg3

Here arg1, arg2, and arg3 are optional arguments to be used in the script's code. They are available from the global constant ARGS. Take a look at the args.jl file as follows:

for arg in ARGS
  println(arg)
end

The julia args.jl 1 Dart C command prints out 1, Dart, and C on consecutive lines.

A script file also can execute other source files by including them in the REPL; for example, main.jl contains include("hello.jl") that will execute the code from hello.jl when called with julia main.jl.

Tip

Downloading the example code

You can download the example code files from your account at http://www.packtpub.com for all the Packt Publishing books you have purchased. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.