Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Constant in Ruby
Answer:
In Ruby, a class constant has a name starting with an uppercase character, e.g.
Foo = 'bar'
puts FooWhere you try to re-define the constant, a warning message will be shown, e.g.
Foo = 'bar'
Foo = '123'
(irb):18: warning: already initialized constant FooGlobal and Local variable in Ruby
Answer:
In Ruby, global variable has a name beginning with $, e.g.
$foo = 'bar'
puts $fooIn contrast, local variable has a name start with a lower case letter or an underscore character, e.g.
foo = 'bar'
puts fooPrint to standard output in different scripting languages
Answer:
To print a string of "Hello World" to the standard output in different scripting languages
1. Perl
print "Hello, World!";
2. Python
print('Hello, World!')
3. PHP
echo "Hello, World!";
4. Ruby
puts "Hello, World!"
List of remote gems on rubyforge.org
Answer:
To list all the available gems on rubyforge.org, use this command:
# gem list --remote
For example, to search for all rails related gems, use
# gem list --remote | grep "\-rails"
List all the installed gems
Answer:
To list all the installed gems on your machine, simply execute the following command:
# gem list --local
*** LOCAL GEMS ***
abstract (1.0.0)
actionmailer (3.0.9)
actionpack (3.0.9)
activemodel (3.0.9)
activerecord (3.0.9)
activeresource (3.0.9)
activesupport (3.0.9)
arel (2.0.10)
builder (2.1.2)
erubis (2.6.6)
i18n (0.5.0)
mail (2.2.19)
mime-types (1.16)
polyglot (0.3.1)
rack (1.2.3)
rack-mount (0.6.14)
rack-test (0.5.7)
rake (0.9.2)
treetop (1.4.9)
tzinfo (0.3.28)
