Forum: Ruby Recommended command line options for new rubyists

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508861510639b56d61eb30e6a28b01d9?d=identicon&s=25 John Maclean (Guest)
on 2006-01-04 20:21
(Received via mailing list)
Hi guys,

There are loooads of ruby docs out there. There are also some good
reference guides under /usr/share/doc/ruby-1.8.3,
/usr/share/doc/ruby-docs-1.8.3 and /usr/share/doc/ruby-libs-1.8.3. What
would the more experienced of you recommend for command line options? So
far I've been using
 ruby -c foo.rb
 ruby -W foo.rb
as they are the simplest :)  I've not really used irb that much as I
haven't seen any advantage in using it.
1fba4539b6cafe2e60a2916fa184fc2f?d=identicon&s=25 unknown (Guest)
on 2006-01-04 20:27
(Received via mailing list)
Hi --

On Thu, 5 Jan 2006, John Maclean wrote:

> haven't seen any advantage in using it.
The ones I use the most are:

   ruby -cw
   ruby -v[e]
   ruby -e
   ruby -p[i.bak][ -e]
   ruby -n[i.bak][ -e]


David

--
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black
508861510639b56d61eb30e6a28b01d9?d=identicon&s=25 John Maclean (Guest)
on 2006-01-04 22:10
(Received via mailing list)
I find it strange that ruby -c foo.rb gives "syntax OK" but ruby -w
foo.rb shows me all of the syntax errors. In the example below i make a
deliberate mistake..

#script

#!/usr/bin/ruby
#Wed Jan  4 06:17:22 GMT 2006
class Menu
        def initialize(welcome, stage, usage)
                @welcome        = print "Welcome to
de-blah-de-blah-de-blah\n\n\n"
                @usage          = usage # we will use this as a user
guide
                @stage          = stage
                #`date`
                #print "which stage are you at?
                #b:- before site work
                #d:- during site work
                #a:- atfer site work
                #q:- quit\!\n"
        end
        def to_s
                "Deskstudy: #@welcome #@usage #@stage"
        end
end

#menu = Menu.new("welcome", "usage", "stage")
menu = Menu.new("welcome", "stage")
menu.inspect
puts menu

#errors

menu.rb:21:in `initialize': wrong number of arguments (2 for 3)
(ArgumentError)
        from menu.rb:21

 On Thu, 5 Jan 2006 04:25:54 +0900
1fba4539b6cafe2e60a2916fa184fc2f?d=identicon&s=25 unknown (Guest)
on 2006-01-04 22:16
(Received via mailing list)
Hi --

On Thu, 5 Jan 2006, John Maclean wrote:

> I find it strange that ruby -c foo.rb gives "syntax OK" but ruby -w
> foo.rb shows me all of the syntax errors. In the example below i
> make a deliberate mistake..

You do, but it's not a syntax error; it's a runtime error.  -c doesn't
run the code, but only checks it for syntax.  -w runs the code.


David
--
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black
57332d67a86eb51e06bf78d2baf42c3c?d=identicon&s=25 �var Arnfjörð Bjarmason (Guest)
on 2006-01-05 18:48
unknown wrote:
> Hi --
>
> On Thu, 5 Jan 2006, John Maclean wrote:
>
>> I find it strange that ruby -c foo.rb gives "syntax OK" but ruby -w
>> foo.rb shows me all of the syntax errors. In the example below i
>> make a deliberate mistake..
>
> You do, but it's not a syntax error; it's a runtime error.  -c doesn't
> run the code, but only checks it for syntax.  -w runs the code.

Or to give a simpler testcase:

$ cat div0
#!/usr/bin/env ruby
puts 5/0

$ ruby -c div0
Syntax OK

$ ruby -w div0
div0:2:in `/': divided by 0 (ZeroDivisionError)
        from div0:2
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