> For the complete documentation index, see [llms.txt](https://docs.bcbi.brown.edu/codiac-for-health/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bcbi.brown.edu/codiac-for-health/computing/julia/repl.md).

# REPL

<mark style="color:$primary;">Julia comes with a full-featured interactive command-line REPL (read-eval-print loop) built into the</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`julia`</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">executable. In addition to allowing quick and easy evaluation of Julia statements, it has a searchable history, tab-completion, many helpful keybindings, and dedicated help</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`?`</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">and shell modes</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`;`</mark><mark style="color:$primary;">.</mark> [\[1\]](#references)&#x20;

This page provides examples of using REPL on the command line.

## Julia REPL Example (local) <a href="#julia_repl_example_local" id="julia_repl_example_local"></a>

* Type `julia` in terminal to launch REPL

<figure><img src="https://content.gitbook.com/content/v4bMBkQ3ZBxkXjskIqBa/blobs/805OZNIgOlnL8JKFfX2V/repl_ex.png" alt="Terminal screen with Julia launched and example commands and output. println(&#x22;hello world!&#x22;) results in hello world!;  word = &#x22;test&#x22; results in &#x22;test&#x22;; typeof(word) results in String; length(word) results in 4; print(word) results in test; exit()"><figcaption></figcaption></figure>

## Julia REPL Help Pages (local) <a href="#julia_repl_help_pages_local" id="julia_repl_help_pages_local"></a>

* Type "?" to enter help pages within REPL
* Type a function from Julia to read help pages (ex: `println`)

<figure><img src="https://content.gitbook.com/content/v4bMBkQ3ZBxkXjskIqBa/blobs/tjg45gmH8MZk2shcHkoN/repl_help.png" alt="Terminal screen with Julia help launched. Type &#x22;?&#x22; for help. From the help?> prompt,  println results in help page for println."><figcaption></figcaption></figure>

## References

1. Julia Contributors. (n.d.). [REPL - Standard Library - Julia Language](https://docs.julialang.org/en/v1/stdlib/REPL/). Retrieved May 1, 2024.&#x20;

## Resources <a href="#documentation" id="documentation"></a>

* Julia Documentation: [The Julia REPL](https://docs.julialang.org/en/v1/stdlib/REPL/)
* [Julia Cheat Sheet](https://juliadocs.github.io/Julia-Cheat-Sheet/) (see REPL)
* [Practice with this web-based Julia REPL](https://julialang.org/learning/tryjulia/)


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