# Julia manual evaluates the expression. Why does it report an error when I run it myself?

**URL:** <https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954>\
**Category:** General Usage\
**Tags:** question\
**Created:** [October 5, 2024, 10:15am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954 "2024-10-05T10:15:29Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![qianlvzhe](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/qianlvzhe/32/212401_2.png) [@qianlvzhe](https://discourse.julialang.org/u/qianlvzhe)\
**Post date:** [October 5, 2024, 10:15am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954/1 "2024-10-05T10:15:30Z")

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![Screenshot 2024-10-05 at 18.05.17](https://global.discourse-cdn.com/julialang/original/3X/6/a/6a5d0b22ff103a5c20473bf67a5049e679d15062.png)  
 ![Screenshot 2024-10-05 at 18.03.23](https://global.discourse-cdn.com/julialang/original/3X/8/7/87c3fc39eb392d5e07c3e1fe191c1c7f40e19261.png)  
 ![Screenshot 2024-10-05 at 17.56.11](https://global.discourse-cdn.com/julialang/original/3X/b/f/bf373ef7a11cb22d36ff2ae88398bcb867155cb9.png)

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**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [October 5, 2024, 10:20am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954/2 "2024-10-05T10:20:32Z")

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The manual has a `;`, not a `,`.

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**Author:** ![qianlvzhe](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/qianlvzhe/32/212401_2.png) [@qianlvzhe](https://discourse.julialang.org/u/qianlvzhe)\
**Post date:** [October 5, 2024, 10:24am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954/3 "2024-10-05T10:24:58Z")

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![Screenshot 2024-10-05 at 18.05.17](https://global.discourse-cdn.com/julialang/original/3X/6/a/6a5d0b22ff103a5c20473bf67a5049e679d15062.png)  
The operation in the terminal is “;”, and the result is also an error.

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**Author:** ![nsajko](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nsajko/32/221187_2.png) [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Post date:** [October 5, 2024, 10:30am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954/4 "2024-10-05T10:30:02Z")

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The error message explains it, you already have a variable `b` in your `Main` name space, coming from module `Html`.

BTW, please use Markdown code blocks and/or quoting in preference to screenshots. See here for more information:

> [@Please read: make it easier to help you](https://discourse.julialang.org/t/please-read-make-it-easier-to-help-you/14757):
>
> Welcome to the Julia Discourse! We are enthusiastic about helping Julia programmers, both beginner and experienced. This public service announcement (PSA) outlines best practices when asking for help. Following these points makes it easier for us to help you and more likely you’ll get a prompt, useful answer. Keywords are highlighted to make it easier to refer to specific points. Choose a descriptive title that captures the key part of your question, eg “plots with multiple axes” instead of …