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execute command in ERB

asked 2015-09-18 13:28:34 -0600

pozcircuitboy gravatar image

Is there a way to execute an external command ("shell command") from a puppet ERB?

I have tried the following with no success:

text=<%= %x(/path/command) %>

text=<%= `/path/command` %>

Both result in


Is this possible in a puppet ERB?

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answered 2015-09-18 15:32:58 -0600

GregLarkin gravatar image

updated 2015-12-11 20:12:47 -0600

I'm not sure why that isn't working for you, but I would recommend a different approach to keep as much code out of your ERB as possible. It's best to use ERB for expression evaluation, simple looping and/or control flow. Other than that, I'd put everything else (where possible) in the Puppet manifest.

You can do something like this:

# In manifest.pp...
$mytext = generate('/path/to/command')

# In myfile.txt.erb...
<%= @mytext -%>

Give that a try and post back here if it works for you or not.


The generate function does some rudimentary checking for legal characters because it does not invoke a shell. If you need to do some more advanced things, then you can spawn a shell yourself like so:

$java_home = generate('/bin/sh', '-c', '/bin/readlink -f $(which java)| sed "s/bin\/java//"')

Hope that helps.

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Did not worked in pp file $java_home = generate('/bin/readlink -f $(which java)| sed "s/bin\/java//"') in erb file JAVA_HOME=<%= @java_home %> Error while puppet agent Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Generators can only contain alphanumerics, file se

manojsamtani gravatar imagemanojsamtani ( 2015-12-10 09:02:50 -0600 )edit

I'll update my answer above with a form that should work around that error for you.

GregLarkin gravatar imageGregLarkin ( 2015-12-11 20:10:38 -0600 )edit

Thank you Greg, It worked (y)

manojsamtani gravatar imagemanojsamtani ( 2015-12-14 02:31:02 -0600 )edit

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Asked: 2015-09-18 13:28:34 -0600

Seen: 2,329 times

Last updated: Dec 11 '15