Having gone through several posts on this issue I still can't add new directory to $LOAD_PATH. I use Ubuntu 12. My $LOAD_PATH is:
2.0.0-p247 :002 > puts $LOAD_PATH
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/x86_64-linux
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby/2.0.0/x86_64-linux
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/x86_64-linux
=> nil
How to add '/home/ajax/Ruby/Projects' to $LOAD_PATH through terminal?
You can add additional entries to the $LOAD_PATH as a command line parameter to your ruby (or irb) command using the -I argument (which can be used multiple times)
$ ruby -I '/home/ajax/Ruby/Projects' -e 'puts $LOAD_PATH'
/home/ajax/Ruby/Projects
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/x86_64-linux
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby/2.0.0/x86_64-linux
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/vendor_ruby
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0
/home/ajax/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/x86_64-linux
in your terminal
export RUBYLIB=/home/ajax/Ruby/Projects
From Add $LOAD_PATH externally
RUBYLIB environment variable is a colon separated list of paths which ruby will prepend the the standard LOAD_PATH. ruby -I path on the command line is also the same as $LOAD_PATH.unshift 'path' in your code. Ruby will also process options from environment var RUBYOPT.
Related
I was reading the following tutorial.
It talked about including files in a Ruby file like require :
require(string) => true or false
Ruby tries to load the library named string, returning true if
successful. If the filename does not resolve to an absolute path, it
will be searched for in the directories listed in $:. If the file has
the extension ".rb", it is loaded as a source file; if the extension
is ".so", ".o", or ".dll", or whatever the default shared library
extension is on the current platform, Ruby loads the shared library as
a Ruby extension. Otherwise, Ruby tries adding ".rb", ".so", and so on
to the name. The name of the loaded feature is added to the array in
$:.
I just want to know what is $: in Ruby and what does $: means.
The variable $: is one of the execution environment variables, which is an array of places to search for loaded files.
The initial value is the value of the arguments passed via the -I command-line option, followed by an installation-defined standard library location.
See Pre-defined variables, $LOAD_PATH is its alias.
Its the load path
Just open in irb terminal and type this $:
This is what you would get. Ofcourse that depends on the ruby ur using.
2.1.1 :009 > $:
=> ["/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/site_ruby/2.1.0", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/site_ruby/2.1.0/x86_64-darwin12.0", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/site_ruby", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/vendor_ruby/2.1.0", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/vendor_ruby/2.1.0/x86_64-darwin12.0", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/vendor_ruby", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0", "/Users/mac/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/x86_64-darwin12.0"]
2.1.1 :010 >
In ruby $ refers to a predefined variable.
In this case, $: is short-hand for $LOAD_PATH. This is the list of directories you can require files from while giving a relative path. In other words, Ruby searches the directories listed in $:
Hope this helps.
I'm working in an IRB shell on a dos CMD
I load a module from a mystuff file
require '.\mystuff'
I change the module in the mystuff file and I type again
require '.\mystuff'
How come the IRB does not pick up the changes in the file when I try to call functions or variables from the newest version of my mystuff module?
require will not load the same file twice. If you want to load the file again, you need to use load. See What is the difference between include and require in Ruby? for more information.
Your Syntax is Wrong
Ruby doesn't use backslashes. You need to use forward slashes, or use File#join.
Your $LOAD_PATH is Wrong
Your $LOAD_PATH (a.k.a $:) is wrong. You need to include the present working directory with:
$: << '.'
in irb, or use Kernel#require_relative in executable or sourced files.
I am currently in
Dropbox/96_2013/work/ror/dmc/dmStaffing/QA/selenium_server_wyatt/spec/2day/units/
I can go into irb and require a file but it's a really long require...
require '/home/durrantm/Dropbox/96_2013/work/ror/dmc/dmStaffing/QA/selenium_server_wyatt/spec/2day/units/login_as_admin_spec.rb'
=> true
I want to use require_relative, as in
$ cd /home/durrantm/Dropbox/96_2013/work/ror/dmc/dmStaffing/QA/selenium_server_wyatt/spec/2day/
$ pwd
/home/durrantm/Dropbox/96_2013/work/ror/dmc/dmStaffing/QA/selenium_server_wyatt/spec/2day
$ irb
irb(main):001:0> require_relative 'units/login_as_admin_spec.rb'
but I get:
LoadError: cannot infer basepath
require_relative requires a file relative to the file the call to require_relative is in. Your call to require_relative isn't in any file, it's in the interactive interpreter, therefore it doesn't work.
You can use the long form of require by explicitly passing the full path:
require './units/login_as_admin_spec.rb'
Or you add the current directory to the $LOAD_PATH and just require as usual:
$LOAD_PATH << '.'
require 'units/login_as_admin_spec'
This is a known bug in ruby:
Ruby bug #4487: require_relative fails in an eval'ed file
If you are using Pry, instead of IRB, this can be fixed by installing the pry-require_relative gem.
gem install pry-require_relative
This worked:
require File.expand_path("../login_as_admin_spec.rb", __FILE__)
require_relative works in the context of the current source file. This is different than the current working directory. I don't believe irb or pry have an understanding of "this current source file" concept; since you're not actually in a file.
In these REPLs, just use a relative path reference require './units/login_as_admin_spec.rb'.
I don't understand the meaning of $:<< "." in Ruby.
I upgraded Ruby to 1.9.1, but a program was not working. My classmate told me that I am supposed to add $:<< "."
What does $:<< "." do?
$: is the variable that holds an array of paths that make up your Ruby's load path
<< appends an item to the end of the array
. refers to the current directory
1 2 3
| | |
V V V
$: << "."
So you are adding the current directory to Ruby's load path
References:
Can be found in the Execution Environment Variables section of of this page from The Pragmatic Programmers Guide
An array of strings, where each string specifies a directory to be searched for Ruby scripts and binary extensions used by the load and require methods. The initial value is the value of the arguments passed via the -I command-line option, followed by an installation-defined standard library location, followed by the current directory (“.”)[Obviously this link is for an older version of Ruby as this is still in there]. This variable may be set from within a program to alter the default search path; typically, programs use $: << dir to append dir to the path.
Can be found in the docs for array at ruby-doc.org.
Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.
Since version 1.9, Ruby doesn't look for required files in the current working directory AKA .. The $LOAD_PATH or $: global variable is an array of paths where Ruby looks for files you require.
By adding $:<< "." to your files, you are actually telling Ruby to include your current directory in the search paths. That overrides new Ruby behavior.
In your example you add working directory (".") to ruby load path ($:).
Working directory (".") was removed from load path (global variable $: or $-I or $LOAD_PATH) in Ruby 1.9 because it was considered a security risk:
Your working directory may be any folder, and your script will require files from this folder if these files have appropriate names. For example you have 2 files in Project1 folder main.rb and init.rb:
==Project1/main1.rb:
$: << "."
require 'init'
==Project1/init.rb:
puts 'init 1'
And you have alike project:
==Project2/main2.rb:
$: << "."
require 'init'
==Project2/init.rb:
puts 'init 2'
If you run Project1 from Project2 folder, then main1.rb will require Project2/init.rb, not Project1/init.rb:
~/Projects/Project2$ ruby ../Project1/main1.rb
init 2 # may be unexpected an dangerous
~/Projects/Project2$ ruby main2.rb
init 2
You can change your working directory in your code, e.g. using Dir.chdir:
ruby-1.9.2-p290 :002 > puts File.expand_path('.')
=> /home/alex/Projects
ruby-1.9.2-p290 :003 > Dir.chdir('..')
ruby-1.9.2-p290 :004 > puts File.expand_path('.')
=> /home/alex
I recommend you to use the following techniques instead of $: << '.':
require_relative (Ruby 1.9 only)
Add folder of the file to the working directory (common approach because it is compatible with Ruby 1.8): $: << File.expand_path('..', __FILE__) etc.. __FILE__ is a reference to the current file name. File.expand_path converts a pathname to an absolute pathname.
I'm trying to include a source code file when I run irb but irb is unable to find it.
For example, say I am in the following directory in terminal:
/dan/rubyapp/
Assume I have a file named "firstapp.rb" in /dan/rubyapp/
I startup irb and from the irb prompt I type
> require "firstapp.rb"
but the file can't be found. If I type "Dir.pwd" it shows as
/dan/rubyapp/
The only way I can get "require" to work is if I include the full path like so
> require "/dan/rubyapp/firstapp.rb"
Is that the only way I can get this to work? All the tutorials I see online simply do "require file_name" so I assumed it would work.
here is the output from $: at irb
ruby-1.9.2-p0 > $:
=> ["/Users/Daniel/.rvm/gems/ruby-1.9.2-p0/gems/wirble-0.1.3/bin",
"/Users/Daniel/.rvm/gems/ruby-1.9.2-p0/gems/wirble-0.1.3/lib",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.4.0",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.4.0",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-
1.9.2-p0/lib/ruby/1.9.1/x86_64-darwin10.4.0"]
The problem is that the current working directory is no longer in your path (as of Ruby 1.9.2). There are a few different ways around the problem.
1) In a ruby file itself, you can use the method require_relative instead of require. This will load a file relative to the loaction of the file containing the require_relative method:
http://extensions.rubyforge.org/rdoc/classes/Kernel.html
require_relative 'firstapp.rb'
This, however, will not work in irb.
2) Your other option is to include the current path in your argument to the require method. This will work in irb or in a ruby file. For instance:
require './firstapp.rb'
The reason this was implemented in ruby was to avoid inadvertently requiring the wrong file if there are different files with the same name in different directories in the path (similar to how *nix does not include the current directory "." in its path)
A couple of things to try:
1) Drop the .rb from the end of your require so you have:
require 'firstapp'
You don't normally add the .rb to a require (only to a load) - have a look here for more details:
http://www.fromjavatoruby.com/2008/10/require-vs-load.html
2) Failing that, make sure the current directory is on your load path - in irb execute:
p $:
and it will print out your ruby load path - check for an entry for "." (mine is the last entry)