Copies from the given src to the given dst, returning the number of bytes copied.
The given src must be one of the following:
The path to a readable file, from which source data is to be read.
An IO-like object, opened for reading and capable of responding to method :readpartial or method :read.
The given dst must be one of the following:
The path to a writable file, to which data is to be written.
An IO-like object, opened for writing and capable of responding to method :write.
The examples here use file t.txt as source:
File.read('t.txt') # => "First line\nSecond line\n\nThird line\nFourth line\n" File.read('t.txt').size # => 47
If only arguments src and dst are given, the entire source stream is copied:
# Paths. IO.copy_stream('t.txt', 't.tmp') # => 47 # IOs (recall that a File is also an IO). src_io = File.open('t.txt', 'r') # => #<File:t.txt> dst_io = File.open('t.tmp', 'w') # => #<File:t.tmp> IO.copy_stream(src_io, dst_io) # => 47 src_io.close dst_io.close
With argument src_length a non-negative integer, no more than that many bytes are copied:
IO.copy_stream('t.txt', 't.tmp', 10) # => 10 File.read('t.tmp') # => "First line"
With argument src_offset also given, the source stream is read beginning at that offset:
IO.copy_stream('t.txt', 't.tmp', 11, 11) # => 11 IO.read('t.tmp') # => "Second line"
Returns an Addrinfo object for remote address obtained by getpeername.
Note that addrinfo.protocol is filled by 0.
TCPSocket.open("www.ruby-lang.org", 80) {|s| p s.remote_address #=> #<Addrinfo: 221.186.184.68:80 TCP> } TCPServer.open("127.0.0.1", 1728) {|serv| c = TCPSocket.new("127.0.0.1", 1728) s = serv.accept p s.remote_address #=> #<Addrinfo: 127.0.0.1:36504 TCP> }
Returns the size (in bytes) of the rest of the [stored string]:
scanner = StringScanner.new('foobarbaz') scanner.rest # => "foobarbaz" scanner.rest_size # => 9 scanner.pos = 3 scanner.rest # => "barbaz" scanner.rest_size # => 6 scanner.terminate scanner.rest # => "" scanner.rest_size # => 0
Returns a string containing the IP address representation in canonical form.
Returns the status of the global “ignore deadlock” condition. The default is false, so that deadlock conditions are not ignored.
See also ::ignore_deadlock=.
Returns the new state. When set to true, the VM will not check for deadlock conditions. It is only useful to set this if your application can break a deadlock condition via some other means, such as a signal.
Thread.ignore_deadlock = true queue = Thread::Queue.new trap(:SIGUSR1){queue.push "Received signal"} # raises fatal error unless ignoring deadlock puts queue.pop
See also ::ignore_deadlock.
With argument pattern, returns an enumerator that uses the pattern to partition elements into arrays (“slices”). An element begins a new slice if element === pattern (or if it is the first element).
a = %w[foo bar fop for baz fob fog bam foy] e = a.slice_before(/ba/) # => #<Enumerator: ...> e.each {|array| p array }
Output:
["foo"] ["bar", "fop", "for"] ["baz", "fob", "fog"] ["bam", "foy"]
With a block, returns an enumerator that uses the block to partition elements into arrays. An element begins a new slice if its block return is a truthy value (or if it is the first element):
e = (1..20).slice_before {|i| i % 4 == 2 } # => #<Enumerator: ...> e.each {|array| p array }
Output:
[1] [2, 3, 4, 5] [6, 7, 8, 9] [10, 11, 12, 13] [14, 15, 16, 17] [18, 19, 20]
Other methods of the Enumerator class and Enumerable module, such as to_a, map, etc., are also usable.
For example, iteration over ChangeLog entries can be implemented as follows:
# iterate over ChangeLog entries. open("ChangeLog") { |f| f.slice_before(/\A\S/).each { |e| pp e } } # same as above. block is used instead of pattern argument. open("ChangeLog") { |f| f.slice_before { |line| /\A\S/ === line }.each { |e| pp e } }
“svn proplist -R” produces multiline output for each file. They can be chunked as follows:
IO.popen([{"LC_ALL"=>"C"}, "svn", "proplist", "-R"]) { |f| f.lines.slice_before(/\AProp/).each { |lines| p lines } } #=> ["Properties on '.':\n", " svn:ignore\n", " svk:merge\n"] # ["Properties on 'goruby.c':\n", " svn:eol-style\n"] # ["Properties on 'complex.c':\n", " svn:mime-type\n", " svn:eol-style\n"] # ["Properties on 'regparse.c':\n", " svn:eol-style\n"] # ...
If the block needs to maintain state over multiple elements, local variables can be used. For example, three or more consecutive increasing numbers can be squashed as follows (see chunk_while for a better way):
a = [0, 2, 3, 4, 6, 7, 9] prev = a[0] p a.slice_before { |e| prev, prev2 = e, prev prev2 + 1 != e }.map { |es| es.length <= 2 ? es.join(",") : "#{es.first}-#{es.last}" }.join(",") #=> "0,2-4,6,7,9"
However local variables should be used carefully if the result enumerator is enumerated twice or more. The local variables should be initialized for each enumeration. Enumerator.new can be used to do it.
# Word wrapping. This assumes all characters have same width. def wordwrap(words, maxwidth) Enumerator.new {|y| # cols is initialized in Enumerator.new. cols = 0 words.slice_before { |w| cols += 1 if cols != 0 cols += w.length if maxwidth < cols cols = w.length true else false end }.each {|ws| y.yield ws } } end text = (1..20).to_a.join(" ") enum = wordwrap(text.split(/\s+/), 10) puts "-"*10 enum.each { |ws| puts ws.join(" ") } # first enumeration. puts "-"*10 enum.each { |ws| puts ws.join(" ") } # second enumeration generates same result as the first. puts "-"*10 #=> ---------- # 1 2 3 4 5 # 6 7 8 9 10 # 11 12 13 # 14 15 16 # 17 18 19 # 20 # ---------- # 1 2 3 4 5 # 6 7 8 9 10 # 11 12 13 # 14 15 16 # 17 18 19 # 20 # ----------
mbox contains series of mails which start with Unix From line. So each mail can be extracted by slice before Unix From line.
# parse mbox open("mbox") { |f| f.slice_before { |line| line.start_with? "From " }.each { |mail| unix_from = mail.shift i = mail.index("\n") header = mail[0...i] body = mail[(i+1)..-1] body.pop if body.last == "\n" fields = header.slice_before { |line| !" \t".include?(line[0]) }.to_a p unix_from pp fields pp body } } # split mails in mbox (slice before Unix From line after an empty line) open("mbox") { |f| emp = true f.slice_before { |line| prevemp = emp emp = line == "\n" prevemp && line.start_with?("From ") }.each { |mail| mail.pop if mail.last == "\n" pp mail } }
Constant time memory comparison. Inputs are hashed using SHA-256 to mask the length of the secret. Returns true if the strings are identical, false otherwise.
Parse a YAML string in yaml. Returns the Psych::Nodes::Stream. This method can handle multiple YAML documents contained in yaml. filename is used in the exception message if a Psych::SyntaxError is raised.
If a block is given, a Psych::Nodes::Document node will be yielded to the block as it’s being parsed.
Raises a Psych::SyntaxError when a YAML syntax error is detected.
Example:
Psych.parse_stream("---\n - a\n - b") # => #<Psych::Nodes::Stream:0x00> Psych.parse_stream("--- a\n--- b") do |node| node # => #<Psych::Nodes::Document:0x00> end begin Psych.parse_stream("--- `", filename: "file.txt") rescue Psych::SyntaxError => ex ex.file # => 'file.txt' ex.message # => "(file.txt): found character that cannot start any token" end
Raises a TypeError when NilClass is passed.
See Psych::Nodes for more information about YAML AST.
Dump a list of objects as separate documents to a document stream.
Example:
Psych.dump_stream("foo\n ", {}) # => "--- ! \"foo\\n \"\n--- {}\n"
Load multiple documents given in yaml. Returns the parsed documents as a list. If a block is given, each document will be converted to Ruby and passed to the block during parsing
Example:
Psych.load_stream("--- foo\n...\n--- bar\n...") # => ['foo', 'bar'] list = [] Psych.load_stream("--- foo\n...\n--- bar\n...") do |ruby| list << ruby end list # => ['foo', 'bar']
Returns true if the named file is readable by the real user and group id of this process. See access(3).
Note that some OS-level security features may cause this to return true even though the file is not readable by the real user/group.
If file_name is readable by others, returns an integer representing the file permission bits of file_name. Returns nil otherwise. The meaning of the bits is platform dependent; on Unix systems, see stat(2).
file_name can be an IO object.
File.world_readable?("/etc/passwd") #=> 420 m = File.world_readable?("/etc/passwd") sprintf("%o", m) #=> "644"
Adds a post-install hook that will be passed an Gem::Installer instance when Gem::Installer#install is called
Adds a hook that will get run after Gem::Specification.reset is run.
Adds a post-uninstall hook that will be passed a Gem::Uninstaller instance and the spec that was uninstalled when Gem::Uninstaller#uninstall is called
Adds a pre-install hook that will be passed an Gem::Installer instance when Gem::Installer#install is called. If the hook returns false then the install will be aborted.
Adds a hook that will get run before Gem::Specification.reset is run.
Adds a pre-uninstall hook that will be passed an Gem::Uninstaller instance and the spec that will be uninstalled when Gem::Uninstaller#uninstall is called