From: "Gerardo Santana Gómez Garrido" <gerardo.santana@...>
Date: 2006-03-27T06:39:54+09:00
Subject: Re: Ruby-esque approaches to adding a line at the beginning of a file.

2006/3/26, Randy Kramer <rhkramer@gmail.com>:
> On our local lug mail list a discussion came up about using Ruby (as opposed
> to Perl) for an application that involved inserting a new line at the front
> of an existing file.
>
> (As a newbie), I proposed an approach like this (with help from the Ruby
> Cookbook which I'm working my way through).
>
> t = "New first line of file.\n"
> t = t + open("sample_file") { |f| f.read }
> open("sample_file", "w") { |f| f.write(t)}
>
> However, it doesn't appear (to me) to be very Ruby-esque--I'm wondering how
> others on this list might approach such a task.
>
> Randy Kramer


If the intention is to do it in the command line, you can write:

ruby -i -pe 'puts "New first line" if ARGF.file.lineno == 1' file

and that will work even with multiple files
--
Gerardo Santana
"Between individuals, as between nations, respect for the rights of
others is peace" - Don Benito Ju�rez
http://santanatechnotes.blogspot.com/