Results for: "Psych"

Invokes system, but silences all output.

Change the current process’s real and effective user ID to that specified by user. Returns the new user ID. Not available on all platforms.

[Process.uid, Process.euid]          #=> [0, 0]
Process::UID.change_privilege(31)    #=> 31
[Process.uid, Process.euid]          #=> [31, 31]

Exchange real and effective user IDs and return the new effective user ID. Not available on all platforms.

[Process.uid, Process.euid]   #=> [0, 31]
Process::UID.re_exchange      #=> 0
[Process.uid, Process.euid]   #=> [31, 0]

Returns true if the real and effective user IDs of a process may be exchanged on the current platform.

Change the current process’s real and effective group ID to that specified by group. Returns the new group ID. Not available on all platforms.

[Process.gid, Process.egid]          #=> [0, 0]
Process::GID.change_privilege(33)    #=> 33
[Process.gid, Process.egid]          #=> [33, 33]

Exchange real and effective group IDs and return the new effective group ID. Not available on all platforms.

[Process.gid, Process.egid]   #=> [0, 33]
Process::GID.re_exchange      #=> 0
[Process.gid, Process.egid]   #=> [33, 0]

Returns true if the real and effective group IDs of a process may be exchanged on the current platform.

Is this tar entry a symlink?

Enumerates through the vertices of the graph. @return [Array<Vertex>] The graph’s vertices.

Passes each grapheme cluster in str to the given block, or returns an enumerator if no block is given. Unlike String#each_char, this enumerates by grapheme clusters defined by Unicode Standard Annex #29 unicode.org/reports/tr29/

"a\u0300".each_char.to_a.size #=> 2
"a\u0300".each_grapheme_cluster.to_a.size #=> 1

Same as Enumerator#with_index(0), i.e. there is no starting offset.

If no block is given, a new Enumerator is returned that includes the index.

Iterates the given block for each element with an arbitrary object, obj, and returns obj

If no block is given, returns a new Enumerator.

Example

to_three = Enumerator.new do |y|
  3.times do |x|
    y << x
  end
end

to_three_with_string = to_three.with_object("foo")
to_three_with_string.each do |x,string|
  puts "#{string}: #{x}"
end

# => foo:0
# => foo:1
# => foo:2

Same as each, but the row index and column index in addition to the element

Matrix[ [1,2], [3,4] ].each_with_index do |e, row, col|
  puts "#{e} at #{row}, #{col}"
end
  # => Prints:
  #    1 at 0, 0
  #    2 at 0, 1
  #    3 at 1, 0
  #    4 at 1, 1

Breaks the buffer into lines that are shorter than maxwidth

Returns the directories in the current shell’s PATH environment variable as an array of directory names. This sets the system_path for all instances of Shell.

Example: If in your current shell, you did:

$ echo $PATH
/usr/bin:/bin:/usr/local/bin

Running this method in the above shell would then return:

["/usr/bin", "/bin", "/usr/local/bin"]

Sets the system_path that new instances of Shell should have as their initial system_path.

path should be an array of directory name strings.

Convenience method for Shell::CommandProcessor.def_system_command. Defines an instance method which will execute the given shell command. If the executable is not in Shell.default_system_path, you must supply the path to it.

Shell.def_system_command('hostname')
Shell.new.hostname # => localhost

# How to use an executable that's not in the default path

Shell.def_system_command('run_my_program', "~/hello")
Shell.new.run_my_program # prints "Hello from a C program!"

Convenience method for Shell::CommandProcessor.undef_system_command

Convenience method for Shell::CommandProcessor.install_system_commands. Defines instance methods representing all the executable files found in Shell.default_system_path, with the given prefix prepended to their names.

Shell.install_system_commands
Shell.new.sys_echo("hello") # => hello

Calls block with two arguments, the item and its index, for each item in enum. Given arguments are passed through to each().

If no block is given, an enumerator is returned instead.

hash = Hash.new
%w(cat dog wombat).each_with_index { |item, index|
  hash[item] = index
}
hash   #=> {"cat"=>0, "dog"=>1, "wombat"=>2}

Iterates the given block for each element with an arbitrary object given, and returns the initially given object.

If no block is given, returns an enumerator.

evens = (1..10).each_with_object([]) { |i, a| a << i*2 }
#=> [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

MRI specific feature

Return all reachable objects from ‘obj’.

This method returns all reachable objects from ‘obj’.

If ‘obj’ has two or more references to the same object ‘x’, then returned array only includes one ‘x’ object.

If ‘obj’ is a non-markable (non-heap management) object such as true, false, nil, symbols and Fixnums (and Flonum) then it simply returns nil.

If ‘obj’ has references to an internal object, then it returns instances of ObjectSpace::InternalObjectWrapper class. This object contains a reference to an internal object and you can check the type of internal object with ‘type’ method.

If ‘obj’ is instance of ObjectSpace::InternalObjectWrapper class, then this method returns all reachable object from an internal object, which is pointed by ‘obj’.

With this method, you can find memory leaks.

This method is only expected to work except with C Ruby.

Example:

ObjectSpace.reachable_objects_from(['a', 'b', 'c'])
#=> [Array, 'a', 'b', 'c']

ObjectSpace.reachable_objects_from(['a', 'a', 'a'])
#=> [Array, 'a', 'a', 'a'] # all 'a' strings have different object id

ObjectSpace.reachable_objects_from([v = 'a', v, v])
#=> [Array, 'a']

ObjectSpace.reachable_objects_from(1)
#=> nil # 1 is not markable (heap managed) object

Calls CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON). Starts tracking memory allocations. See also OpenSSL.print_mem_leaks.

This is available only when built with a capable OpenSSL and –enable-debug configure option.

Specifies a character to be appended on completion. Nothing will be appended if an empty string (“”) or nil is specified.

For example:

require "readline"

Readline.readline("> ", true)
Readline.completion_append_character = " "

Result:

>
Input "/var/li".

> /var/li
Press TAB key.

> /var/lib
Completes "b" and appends " ". So, you can continuously input "/usr".

> /var/lib /usr

NOTE: Only one character can be specified. When “string” is specified, sets only “s” that is the first.

require "readline"

Readline.completion_append_character = "string"
p Readline.completion_append_character # => "s"

Raises NotImplementedError if the using readline library does not support.