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I'm writing a bit of Ruby for use on the command line, but the shell is interfering too much - is there a way to turn off interpolation for the entire line? I know I can escape certain characters, but I'm looking for a blanket ban.

For example, I've got the shell set not to add to history if it begins with a blank space.

Any help with this is much appreciated.

I don't think I made myself clear, my apologies. An example:

ruby -pi -e 'gsub(/(find)(this)/, "#{$1} #{$2}")'

The shell won't interpolate those $ numbers because it's wrapped in single quotes, but sometimes the code will need to include quotes. Ruby is quite helpful in this, you can use other special characters to change quotes but then it all starts getting a bit messy, and it won't be as straightforward as above. What I'd like is something more like:

%% ruby -pi -e 'gsub(/(find)(this)/, "#{$1} #{$2}")'

Where %% would turn off interpolation by the shell for the rest of the line.

ian
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  • Can you give us an example ? – user9517 Aug 15 '12 at 11:41
  • What do you mean by interpolation? My understanding of it doesn't make any sense in your context. – KingyCronus Aug 15 '12 at 12:49
  • @KingyCronus I want the shell to ignore any special characters, things it thinks are variables etc etc i.e. the line I give is given to the ruby interpreter as is, literal. I don't want to have to escape anything. – ian Aug 15 '12 at 14:05

2 Answers2

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How about using a function that will read from a prompt and then execute literally what you type in?

function f { read -p"> " c; $c; }

In use, it will look like:

$ f
> echo $var
$var
Grisha Levit
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  • I'm going to give this a try, it's a very interesting idea! +1 for a bit of sideways thinking :) – ian Aug 17 '12 at 19:32
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When you create your command line, continue to use the single quotes, but escape (use \) any internal single-quotes and will replace them with single-quotes without ending the quoting of the string as a whole.

Marnen Laibow-Koser
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Walter
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