Gets problem - strange

ruby-talk
1

This is a problem that was pointed out by Esteban Velazquez.

   % cat gets2.rb
   #!/usr/bin/ruby

   print "getting "; puts gets

Sending the app arguments returns an error:

   % ruby gets2.rb fred
   gets2.rb:3:in `gets': No such file or directory - fred (Errno::ENOENT)
           from gets2.rb:3

But, with no arguments, it runs ok.

   % ruby gets2.rb
   getting foo
   foo

The problem is eluding me now. Any help would be appreciated.

Jim Freeze

2

It works like perl in this regard, expecting the arguments on the command
line to be files the lines of which you want read.

% echo -e "foo\nbar" > some_file
% echo "while l = gets; p l end" > gets.rb
% ruby gets.rb some_file
"foo\n"
"bar\n"

marcel

···

On Mon, Jun 12, 2006 at 03:21:18AM +0900, Jim Freeze wrote:

This is a problem that was pointed out by Esteban Velazquez.

  % cat gets2.rb
  #!/usr/bin/ruby

  print "getting "; puts gets

Sending the app arguments returns an error:

  % ruby gets2.rb fred
  gets2.rb:3:in `gets': No such file or directory - fred
(Errno::ENOENT)
          from gets2.rb:3

But, with no arguments, it runs ok.

  % ruby gets2.rb
  getting foo
  foo

The problem is eluding me now. Any help would be appreciated.

--
Marcel Molina Jr. <marcel@vernix.org>

3

Check the documentation for the method:
http://ruby-doc.org/core/classes/Kernel.html#M002976

"Returns (and assigns to $_) the next line from the list of files in ARGV (or $*), or from standard input if no files are present on the command line."

You can explicitly use $stdin.gets or STDIN.gets to get the behaviour you want.

matthew smillie.

···

On Jun 11, 2006, at 19:21, Jim Freeze wrote:

This is a problem that was pointed out by Esteban Velazquez.

  % cat gets2.rb
  #!/usr/bin/ruby

  print "getting "; puts gets

Sending the app arguments returns an error:

  % ruby gets2.rb fred
  gets2.rb:3:in `gets': No such file or directory - fred (Errno::ENOENT)
          from gets2.rb:3

But, with no arguments, it runs ok.

4

So, I suppose that one needs to empty out ARGV before using gets?

Wow. Really?!

Jim Freeze

···

On Jun 11, 2006, at 1:36 PM, Marcel Molina Jr. wrote:

It works like perl in this regard, expecting the arguments on the command
line to be files the lines of which you want read.

% echo -e "foo\nbar" > some_file
% echo "while l = gets; p l end" > gets.rb
% ruby gets.rb some_file
"foo\n"
"bar\n"

5

Jim Freeze wrote:

···

On Jun 11, 2006, at 1:36 PM, Marcel Molina Jr. wrote:

It works like perl in this regard, expecting the arguments on the command
line to be files the lines of which you want read.

% echo -e "foo\nbar" > some_file
% echo "while l = gets; p l end" > gets.rb
% ruby gets.rb some_file
"foo\n"
"bar\n"

So, I suppose that one needs to empty out ARGV before using gets?

Wow. Really?!

ARGF really. This bites me sometimes. I have difficulty
remembering the details of how it works.

Hal

6

You want IO#gets not Kernel#gets.

  STDIN.gets

marcel

···

On Mon, Jun 12, 2006 at 03:44:53AM +0900, Jim Freeze wrote:

On Jun 11, 2006, at 1:36 PM, Marcel Molina Jr. wrote:

>It works like perl in this regard, expecting the arguments on the
>command
>line to be files the lines of which you want read.
>
>% echo -e "foo\nbar" > some_file
>% echo "while l = gets; p l end" > gets.rb
>% ruby gets.rb some_file
>"foo\n"
>"bar\n"

So, I suppose that one needs to empty out ARGV before using gets?

Wow. Really?!

--
Marcel Molina Jr. <marcel@vernix.org>