From: Ned Konz <ned@...>
Date: 2002-06-14T09:11:40+09:00
Subject: Re: UNIX pipes

On Thursday 13 June 2002 04:13 pm, David Douthitt wrote:
> I thought I could do:
>
> @snaptime = `/usr/contrib/bin/gunzip -lv #{file} | /usr/bin/sed
> 's/^[^ ]* [^ ]* \(... .. ..:..\).*/\1/'`.chomp p @snaptime
>
> ...and it should (to me, anyway) return:
>
> "Jun 12 13:54"
>
> ...instead of the odd result of:
>
> "\001"
>
> What gives?  That's not a returned error code, is it?

No, it's the \1 you asked for in the sed command...

Ruby quoting doesn't work like shell quoting: single quotes inside 
double quotes or backticks don't mean anything special. So Ruby (not 
sed) got the \1, and decided it meant octal 1 (\001).

> I tried "system()" but it doesn't return a string the way I want,
> and it didn't work anyway.
>
> What's the accepted way to use a UNIX pipe?  I wound up using Ruby
> commands instead of sed...


-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE