# System() help

**URL:** <https://www.ruby-forum.com/t/system-help/71573>\
**Category:** Ruby\
**Created:** [February 21, 2006, 9:26pm UTC](https://www.ruby-forum.com/t/system-help/71573 "2006-02-21T21:26:54Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![zaq](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/f04885/32.png) [@zaq](https://www.ruby-forum.com/u/zaq)\
**Post date:** [February 21, 2006, 9:26pm UTC](https://www.ruby-forum.com/t/system-help/71573/1 "2006-02-21T21:26:54Z")

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are there any docs describing how to get stderr vs stdout from a  
system()?

@myresult = system(mycmd)  
works only if I have stdout returned but not stderr.

thanks

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**Author:** ![zaq](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/f04885/32.png) [@zaq](https://www.ruby-forum.com/u/zaq)\
**Post date:** [February 21, 2006, 9:31pm UTC](https://www.ruby-forum.com/t/system-help/71573/2 "2006-02-21T21:31:49Z")

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zac elston wrote:

> are there any docs describing how to get stderr vs stdout from a  
> system()?
> 
> @myresult = system(mycmd)  
> works only if I have stdout returned but not stderr.

You might want to look at IO.popen or Open3 from the  
stdlib (Open3.popen) if you need anything more than  
your platform’s C system() call.

> thanks

E

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<div class="post-metadata">

**Author:** ![zaq](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/f04885/32.png) [@zaq](https://www.ruby-forum.com/u/zaq)\
**Post date:** [February 21, 2006, 9:40pm UTC](https://www.ruby-forum.com/t/system-help/71573/3 "2006-02-21T21:40:46Z")

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Look up ‘open3’ in the standard library:  
[http://ruby-doc.org/stdlib/libdoc/open3/rdoc/index.html](http://ruby-doc.org/stdlib/libdoc/open3/rdoc/index.html)

require “open3”  
stdin, stdout, stderr = Open3.popen3(‘man ruby’)

(You don’t have to use stdin if you don’t want to)