Comments on: 6 Ways to Run Shell Commands in Ruby

By: Ilya

Ilya — Wed, 14 Mar 2007 08:58:00 +0000

Thank you! Nice review.

By: Wayne E. Seguin

Wayne E. Seguin — Thu, 05 Jul 2007 22:07:23 +0000

Don’t forget the %x{whoami} which is the delimited form of the backquote `whoami`.

By: Marius

Marius — Fri, 07 Sep 2007 11:11:37 +0000

Hey! Thanks for the overview! Do you happen to know how I can pass a ruby variable to the shell command that needs to be executed? Something like this:

filename = ‘test.tar’ result = `tar xfv` + filename

Of course this does not work, but how do I make it work ? I have been googling for 30 minutes now and I can’t find anything. Greetings from Bonn (DE)

By: Michael

Michael — Sat, 15 Sep 2007 00:18:40 +0000

Marius - you can use

exit_code = system(”tar xfv #{filename}”)

Make sure to use double quotes, not single quotes.

If you need to capture output, use Open3.popen with the same double-quoted string.

By: Jason Campbell

Jason Campbell — Sat, 22 Sep 2007 07:50:30 +0000

Thanks! Seriously. I found this after almost an hour of scouring google. This is just what I needed!

I added a line to Simon Gate’s Basecamp post-commit hook to automatically update a working copy of my repository using the backtick method. I saw the method before but since I am a noob to ruby I didn’t quite get it until I found your article. Thanks again!

By: Floyd

Floyd — Fri, 28 Sep 2007 02:41:58 +0000

Nice summary. It was helpful.

By: Garrett Smith

Garrett Smith — Thu, 18 Oct 2007 17:46:13 +0000

Good write-up, but you forgot to mention that a few of these methods don’t work on certian OSes, such as Windows.

By: james

james — Sun, 21 Oct 2007 11:45:51 +0000

Very useful - Answered a lot of key questions

By: JeanW

JeanW — Thu, 14 Feb 2008 20:12:30 +0000

Great article! We actually ended up going with a simple solution to get our stderr on Windows– we just redirected stderr to stdout inside the backticsk, e.g.

`#{command} #{args} 2>&1`

No need to install a new gem on every machine!

By: Murilo

Murilo — Thu, 28 Feb 2008 01:54:52 +0000

Good tutorial. You just forgot to metion that I need to do require “open3″ at the beginning of Section “Open3″; you only did it at the third block of code. I also couldn’t use open4 on Debian, even after doing gem instal open4, does someone know the reason? (I don’t have any experience on Ruby programming, just found the article and tried it out)

By: links for 2008-03-11 « Bloggitation

links for 2008-03-11 « Bloggitation — Tue, 11 Mar 2008 00:19:22 +0000

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By: IceskYsl

IceskYsl — Tue, 08 Apr 2008 15:27:47 +0000

I notice a error like this:

Code: logger.info(”rar a #{local_dir_name} #{local_dir_name}”) oo= %x{rar a #{local_dir_name} #{local_dir_name}} logger.info(”oo=#{oo}”)

Output: rar a 1207666290_2 1207666290_2 oo= Program aborted

can anybody give me a hand?

By: IceskYsl

IceskYsl — Tue, 08 Apr 2008 15:30:29 +0000

and in my localhost,it’s ok,output like this:

Evaluation copy. Please register.

Creating archive 1207667932_2.rar

Adding 1207667932_2/datas.csv OK Adding 1207667932_2/images OK Adding 1207667932_2 OK Done ——–

By: Max

Max — Fri, 11 Apr 2008 16:13:29 +0000

I’m trying to do what Marius is doing, but executing “tainted” input instead. Does anyone know if there is a way to escape shell arguments so they’re safe?

Also, you can install the win32-open3 gem to get this to work on Windows, btw.

Oh, and nice article

By: daniel rails

daniel rails — Mon, 14 Apr 2008 07:59:49 +0000

Hey Nate, thanks for article, this was exactly what I was searching for! Greets, Daniel

By: kingtutt

kingtutt — Sun, 20 Apr 2008 12:38:07 +0000

You’ve restored my faith! And inspired me to use ruby for in place of bash scripting for system administration tasks…and that’s just awesome.

By: wdso

wdso — Thu, 24 Jul 2008 23:12:06 +0000

Brilliant summary. One question though… what about threads?