Results for: "String# "

Returns the name of the file referenced by the given link. Not available on all platforms.

File.symlink("testfile", "link2test")   #=> 0
File.readlink("link2test")              #=> "testfile"

Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. Since the underlying implementation relies on the unlink(2) system call, the type of exception raised depends on its error type (see linux.die.net/man/2/unlink) and has the form of e.g. Errno::ENOENT.

See also Dir::rmdir.

Truncates the file file_name to be at most integer bytes long. Not available on all platforms.

f = File.new("out", "w")
f.write("1234567890")     #=> 10
f.close                   #=> nil
File.truncate("out", 5)   #=> 0
File.size("out")          #=> 5

Returns a new string formed by joining the strings using "/".

File.join("usr", "mail", "gumby")   #=> "usr/mail/gumby"

Like File#stat, but does not follow the last symbolic link; instead, returns a File::Stat object for the link itself:

File.symlink('t.txt', 'symlink')
f = File.new('symlink')
f.stat.size  # => 47
f.lstat.size # => 11

Truncates file to at most integer bytes. The file must be opened for writing. Not available on all platforms.

f = File.new("out", "w")
f.syswrite("1234567890")   #=> 10
f.truncate(5)              #=> 0
f.close()                  #=> nil
File.size("out")           #=> 5

Return true if the named file exists.

file_name can be an IO object.

“file exists” means that stat() or fstat() system call is successful.

Returns true if the named file is writable by the effective user and group id of this process. See eaccess(3).

Note that some OS-level security features may cause this to return true even though the file is not writable by the effective user/group.

Returns true if filepath points to a symbolic link, false otherwise:

symlink = File.symlink('t.txt', 'symlink')
File.symlink?('symlink') # => true
File.symlink?('t.txt')   # => false

Returns true if the named file has the sticky bit set.

file_name can be an IO object.

Returns a string which represents the encoding for programmers.

Encoding::UTF_8.inspect       #=> "#<Encoding:UTF-8>"
Encoding::ISO_2022_JP.inspect #=> "#<Encoding:ISO-2022-JP (dummy)>"

Returns the list of loaded encodings.

Encoding.list
#=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>,
      #<Encoding:ISO-2022-JP (dummy)>]

Encoding.find("US-ASCII")
#=> #<Encoding:US-ASCII>

Encoding.list
#=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>,
      #<Encoding:US-ASCII>, #<Encoding:ISO-2022-JP (dummy)>]

Search the encoding with specified name. name should be a string.

Encoding.find("US-ASCII")  #=> #<Encoding:US-ASCII>

Names which this method accept are encoding names and aliases including following special aliases

“external”

default external encoding

“internal”

default internal encoding

“locale”

locale encoding

“filesystem”

filesystem encoding

An ArgumentError is raised when no encoding with name. Only Encoding.find("internal") however returns nil when no encoding named “internal”, in other words, when Ruby has no default internal encoding.

Rewinds the enumeration sequence to the beginning.

If the enclosed object responds to a “rewind” method, it is called.

Creates a printable version of e.

Returns a Digest subclass by name in a thread-safe manner even when on-demand loading is involved.

require 'digest'

Digest("MD5")
# => Digest::MD5

Digest(:SHA256)
# => Digest::SHA256

Digest(:Foo)
# => LoadError: library not found for class Digest::Foo -- digest/foo

Returns a string containing a human-readable representation of obj. The default inspect shows the object’s class name, an encoding of its memory address, and a list of the instance variables and their values (by calling inspect on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.

[ 1, 2, 3..4, 'five' ].inspect   #=> "[1, 2, 3..4, \"five\"]"
Time.new.inspect                 #=> "2008-03-08 19:43:39 +0900"

class Foo
end
Foo.new.inspect                  #=> "#<Foo:0x0300c868>"

class Bar
  def initialize
    @bar = 1
  end
end
Bar.new.inspect                  #=> "#<Bar:0x0300c868 @bar=1>"

Return this exception’s class name and message.

Returns any backtrace associated with the exception. The backtrace is an array of strings, each containing either “filename:lineNo: in ‘method”’ or “filename:lineNo.”

def a
  raise "boom"
end

def b
  a()
end

begin
  b()
rescue => detail
  print detail.backtrace.join("\n")
end

produces:

prog.rb:2:in `a'
prog.rb:6:in `b'
prog.rb:10

In the case no backtrace has been set, nil is returned

ex = StandardError.new
ex.backtrace
#=> nil

Return the status value associated with this system exit.

Invokes Module.append_features on each parameter in reverse order.

Refine mod in the receiver.

Returns a module, where refined methods are defined.

Returns an array of modules defined within the receiver.

module A
  refine Integer do
  end

  refine String do
  end
end

p A.refinements

produces:

[#<refinement:Integer@A>, #<refinement:String@A>]

In the first form, returns an array of the names of all constants accessible from the point of call. This list includes the names of all modules and classes defined in the global scope.

Module.constants.first(4)
   # => [:ARGF, :ARGV, :ArgumentError, :Array]

Module.constants.include?(:SEEK_SET)   # => false

class IO
  Module.constants.include?(:SEEK_SET) # => true
end

The second form calls the instance method constants.

Callback invoked whenever the receiver is included in another module or class. This should be used in preference to Module.append_features if your code wants to perform some action when a module is included in another.

module A
  def A.included(mod)
    puts "#{self} included in #{mod}"
  end
end
module Enumerable
  include A
end
 # => prints "A included in Enumerable"