From: Steven Lumos <steven@...>
Date: 2007-02-14T11:18:02+09:00
Subject: Re: ENV['COLUMNS']

Ryan Davis <ryand-ruby@zenspider.com> writes:

> On Feb 10, 2007, at 3:25 AM, pedro mg wrote:
>
>> Hi,
>>
>> in irb I can have access to ENV['COLUMNS'] for the # of columns in
>> the shell, and works fine.
>> But inside a script (ruby script.rb), I can't have access to that
>> hash key and value.
>> I've done a:
>>
>> puts ENV.to_a
>>
>> and i can not see both COLUMNS and LINES
>> What would be the problem ?
>
> COLUMNS isn't exported. You shouldn't be able to see it within your
> irb session without exporting it or doing something else special.
>
> % echo $COLUMNS
> 80
> % ruby -e 'p ENV.keys.grep(/COL/)'
> []
> % irb
>>> p ENV.keys.grep(/COL/)
> []
> => nil
>>> ^d

$ echo $COLUMNS
80
$ ruby -e 'p ENV["COLUMNS"]'
nil
$ irb
>> ENV["COLUMNS"]
=> "80"
$ irb --noreadline
>> ENV["COLUMNS"]
=> nil
>> ^D
$ cd /src/devel/readline/readline-4.2
$ grep setenv *.c
shell.c:  setenv ("LINES", b, 1);
shell.c:  setenv ("COLUMNS", b, 1);

Most people probably don't consider using irb with readline "special".
It's probably only in your shell due to readline, libedit, or similar
in the first place.

$ /bin/ksh
$ echo $COLUMNS

$

Steve