From: Robert Klemme <shortcutter@...>
Date: 2011-08-29T04:57:18+09:00
Subject: Re: convert unix one-liner to ruby one-liner

On Sun, Aug 28, 2011 at 9:27 PM, Tim R. <timrandg@gmail.com> wrote:
> I would like to append a carriage return to all .txt files. I can do it
> with unix scripting on the command line, but would like to know what the
> equivalent ruby solution is (out of curiosity).
>
> unix solution:
> for file in *.txt; do echo >> $file; done

Be careful to use double quotes if there may be spaces in file names.

> The following also works:
>
> for file in *.txt; do ruby -p -i -e 'END{puts}' $file; done
>
> But simplifying to avoid wrapping in a unix script fails to hit any file
> except the first from the *.seq list (I don't understand why, since

What "*.seq list"?

> usually ruby one-liners can run batch with this input).
>
> ruby -p -i -e 'END{puts}' *.txt

This cannot work since END is invoked only _once_.  Try instead:

$ ruby -e 'ARGV.each {|f| File.open(f,"a") {|io| io.puts}}' *.txt
$ ruby -e 'Dir["*.txt"].each {|f| File.open(f,"a") {|io| io.puts}}'

You can even do

$ ruby -e 'ARGV.each {|f| File.open(f,"a",&:puts)}' *.txt
$ ruby -e 'Dir["*.txt"].each {|f| File.open(f,"a",&:puts)}'

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/