From: Hidetoshi NAGAI <nagai@...>
Date: 2006-11-27T11:05:20+09:00
Subject: Re: Truncating string set on $0

From: "Joao Pedrosa" <joaopedrosa@gmail.com>
Subject: Truncating string set on $0
Date: Mon, 27 Nov 2006 09:36:51 +0900
Message-ID: <ca2428780611261636w298d6ff8v2ae3f49bea2340bd@mail.gmail.com>
> To make it work transparently, I used to set the $0 variable to
> the filename of the second script, and everything, for months,
> ran smoothly. That is, until today. Today I noticed that a large
> filename string could be truncated, and it seems that the length
> depends on the initial command for launching Ruby.

I got same problem on Ruby/TkORCA.
Based on advice on ruby-dev ML, I wrote the following 
for a script on a sandbox.
If you don't need the full string on 'ps' command, 
you'll be able to avoid the problem by similar way.
----------------------------------------------------------------------
#
#  replace_progname_globalvar.rb
#
#                             by Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)
#
###########################################
#  replace $0 and $PROGRAM_NAME
###########################################
progname_obj = Object.new
progname_obj.instance_variable_set(:@progname_tbl, Hash.new('tkorca'.freeze))

class << progname_obj
  def __set_progname_for_ip__(name, ip)
    TkORCA.security_check(5) if MultiTkIp.__getip != ip
    @progname_tbl[ip] = name.to_s
  end

  def __set_progname__(name)
    @progname_tbl[MultiTkIp.__getip] = name.to_s
  end

  def to_str
    @progname_tbl[MultiTkIp.__getip]
  end
  alias to_s to_str
  alias inspect to_str

  def ===(other)
    other === self.to_str
  end

  def ==(other)
    other == self.to_str
  end

  def equal?(other)
    other.equal?(self.to_str)
  end

  def eql?(other)
    other.eql?(self.to_str)
  end

  def method_missing(id, *args)
    self.to_str.__send__(id, *args)
  end
end

progname_obj.__set_progname__($0)
$program_name = progname_obj

alias $REAL_PROGRAM_NAME $0
alias $PROGRAM_NAME $program_name
alias $0 $program_name

trace_var(:$program_name){|val|
  unless progname_obj.object_id == val.object_id
    program_obj.__set_progname__(val)
    $program_name = progname_obj
  end
}
----------------------------------------------------------------------
-- 
Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)