Behaves like IO#write
, except that it:
Writes at the given offset
(in bytes).
Disregards, and does not modify, the stream’s position (see Position).
Bypasses any user space buffering in the stream.
Because this method does not disturb the stream’s state (its position, in particular), pwrite
allows multiple threads and processes to use the same IO object for writing at various offsets.
f = File.open('t.tmp', 'w+') # Write 6 bytes at offset 3. f.pwrite('ABCDEF', 3) # => 6 f.rewind f.read # => "\u0000\u0000\u0000ABCDEF" f.close
Not available on some platforms.
Writes each of the given objects
to self
, which must be opened for writing (see Access Modes); returns the total number bytes written; each of objects
that is not a string is converted via method to_s
:
$stdout.write('Hello', ', ', 'World!', "\n") # => 14 $stdout.write('foo', :bar, 2, "\n") # => 8
Output:
Hello, World! foobar2
Related: IO#read
.
Reads and returns the next 1-character string from the stream; raises EOFError
if already at end-of-stream. See Character IO.
f = File.open('t.txt') f.readchar # => "F" f.close f = File.open('t.rus') f.readchar.ord # => 1090 f.close
Invokes Posix system call ioctl(2), which issues a low-level command to an I/O device.
Issues a low-level command to an I/O device. The arguments and returned value are platform-dependent. The effect of the call is platform-dependent.
If argument argument
is an integer, it is passed directly; if it is a string, it is interpreted as a binary sequence of bytes.
Not implemented on all platforms.
Returns the path associated with the IO
, or nil
if there is no path associated with the IO
. It is not guaranteed that the path exists on the filesystem.
$stdin.path # => "<STDIN>" File.open("testfile") {|f| f.path} # => "testfile"
Removes all elements and returns self.
set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}> set.clear #=> #<Set: {}> set #=> #<Set: {}>
Returns the values in self
as an array:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.to_a # => ["Joe Smith", "123 Maple, Anytown NC", 12345]
Related: members
.
Leaves exclusive section.
Enters exclusive section and executes the block. Leaves the exclusive section automatically when the block exits. See example under MonitorMixin
.
Returns clean pathname of self
with consecutive slashes and useless dots removed. The filesystem is not accessed.
If consider_symlink
is true
, then a more conservative algorithm is used to avoid breaking symbolic linkages. This may retain more ..
entries than absolutely necessary, but without accessing the filesystem, this can’t be avoided.
See Pathname#realpath
.
Creates a full path, including any intermediate directories that don’t yet exist.
See FileUtils.mkpath
and FileUtils.mkdir_p
Returns the real (absolute) pathname for self
in the actual filesystem.
Does not contain symlinks or useless dots, ..
and .
.
All components of the pathname must exist when this method is called.
Returns the real (absolute) pathname of self
in the actual filesystem.
Does not contain symlinks or useless dots, ..
and .
.
The last component of the real pathname can be nonexistent.
Spawns the specified command on a newly allocated pty. You can also use the alias ::getpty
.
The command’s controlling tty is set to the slave device of the pty and its standard input/output/error is redirected to the slave device.
env
is an optional hash that provides additional environment variables to the spawned pty.
# sets FOO to "bar" PTY.spawn({"FOO"=>"bar"}, "printenv", "FOO") do |r, w, pid| p r.read #=> "bar\r\n" ensure r.close; w.close; Process.wait(pid) end # unsets FOO PTY.spawn({"FOO"=>nil}, "printenv", "FOO") do |r, w, pid| p r.read #=> "" ensure r.close; w.close; Process.wait(pid) end
command
and command_line
are the full commands to run, given a String
. Any additional arguments
will be passed to the command.
In the non-block form this returns an array of size three, [r, w, pid]
.
In the block form these same values will be yielded to the block:
r
A readable IO
that contains the command’s standard output and standard error
w
A writable IO
that is the command’s standard input
pid
The process identifier for the command.
This method does not clean up like closing IOs or waiting for child process, except that the process is detached in the block form to prevent it from becoming a zombie (see Process.detach
). Any other cleanup is the responsibility of the caller. If waiting for pid
, be sure to close both r
and w
before doing so; doing it in the reverse order may cause deadlock on some OSes.
This method is called when weak warning is produced by the parser. fmt
and args
is printf style.
This method is called when strong warning is produced by the parser. fmt
and args
is printf style.
enable the socket option IPV6_V6ONLY if IPV6_V6ONLY is available.