From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2010-08-17T19:52:37+09:00
Subject: Re: Write to file

On Tue, Aug 17, 2010 at 12:46 PM, T. A. <tigrib85-forum@yahoo.de> wrote:
> Hi,
>
> I'm trying to write to a new file, wich I'm creating by
>
> file=File.new('file.txt', 'w')
>
> This works fine so far, the file is created in my working folder and
> contains the text I'm putting in.
>
> Now I want the user to input the filename, so I modified my source code
> like this:
>
>
> print "Please insert file name: "
>
> file_name=gets
>
> file=File.new(file_name+'.txt', 'w')
>
> Running the Programm and inputting 'test' (without the ''), I get the
> following Error:
>
> ..\rubyfile.rb:116:in `initialize': Invalid argument - test
> (Errno::EINVAL)
> .txt
>        from ..\rubyfile.rb:116:in `new'
>        from ..\rubyfile.rb:116
>

The problem is that gets returns the \n at the end of the string, so
file_name + ".txt" is "test\n.txt", which seems to be an invalid
filename. Try this:

file_name = gets.chomp


> I have no idea, what's going wrong... Since file_name is a string,
> file_name+'.txt' ought to be a string too, and thus a valid argument for
> the initializer method of File, or not?

BTW, use the block form of File.open, it ensures that the file is closed:

File.open("#{file_name}.txt", "w") do |file|
   ...
end

Jesus.