Updates modification times (mtime) and access times (atime) of the entries given by the paths in list (a single path or an array of paths); returns list if it is an array, [list] otherwise.
By default, creates an empty file for any path to a non-existent entry; use keyword argument nocreate to raise an exception instead.
Argument list or its elements should be interpretable as paths.
Examples:
# Single path. f = File.new('src0.txt') # Existing file. f.atime # => 2022-06-10 11:11:21.200277 -0700 f.mtime # => 2022-06-10 11:11:21.200277 -0700 FileUtils.touch('src0.txt') f = File.new('src0.txt') f.atime # => 2022-06-11 08:28:09.8185343 -0700 f.mtime # => 2022-06-11 08:28:09.8185343 -0700 # Array of paths. FileUtils.touch(['src0.txt', 'src0.dat'])
Keyword arguments:
mtime: time - sets the entry’s mtime to the given time, instead of the current time.
nocreate: true - raises an exception if the entry does not exist.
noop: true - does not touch entries; returns nil.
verbose: true - prints an equivalent command:
FileUtils.touch('src0.txt', noop: true, verbose: true) FileUtils.touch(['src0.txt', 'src0.dat'], noop: true, verbose: true) FileUtils.touch(path, noop: true, verbose: true)
Output:
touch src0.txt touch src0.txt src0.dat touch src0.txt
Related: FileUtils.uptodate?.
Returns an array of the string names of FileUtils methods that accept one or more keyword arguments:
FileUtils.commands.sort.take(3) # => ["cd", "chdir", "chmod"]
Set the changed state of this object. Notifications will be sent only if the changed state is true.
state
Boolean indicating the changed state of this Observable.
Returns true if this object’s state has been changed since the last notify_observers call.
The standard configuration object for gems.
Use the given configuration object (which implements the ConfigFile protocol) as the standard configuration object.
The path to the data directory specified by the gem name. If the package is not available as a gem, return nil.
A Zlib::Deflate.deflate wrapper
Retrieve the PathSupport object that RubyGems uses to lookup files.
Initialize the filesystem paths to use from env. env is a hash-like object (typically ENV) that is queried for ‘GEM_HOME’, ‘GEM_PATH’, and ‘GEM_SPEC_CACHE’ Keys for the env hash should be Strings, and values of the hash should be Strings or nil.
Set array of platforms this RubyGems supports (primarily for testing).
Array of platforms this RubyGems supports.
Returns the arc tangent of y and x in radians.
Domain of y: [-INFINITY, INFINITY].
Domain of x: [-INFINITY, INFINITY].
Range: [-PI, PI].
Examples:
atan2(-1.0, -1.0) # => -2.356194490192345 # -3*PI/4 atan2(-1.0, 0.0) # => -1.5707963267948966 # -PI/2 atan2(-1.0, 1.0) # => -0.7853981633974483 # -PI/4 atan2(0.0, -1.0) # => 3.141592653589793 # PI
Returns the arc tangent of x.
Domain: [-INFINITY, INFINITY].
Range: [-PI/2, PI/2] .
Examples:
atan(-INFINITY) # => -1.5707963267948966 # -PI2 atan(-PI) # => -1.2626272556789115 atan(-PI/2) # => -1.0038848218538872 atan(0.0) # => 0.0 atan(PI/2) # => 1.0038848218538872 atan(PI) # => 1.2626272556789115 atan(INFINITY) # => 1.5707963267948966 # PI/2
Returns the inverse hyperbolic tangent of x.
Domain: [-1, 1].
Range: [-INFINITY, INFINITY].
Examples:
atanh(-1.0) # => -Infinity atanh(0.0) # => 0.0 atanh(1.0) # => Infinity
Returns the value of the gamma function for x.
Domain: (-INFINITY, INFINITY] excluding negative integers.
Range: [-INFINITY, INFINITY].
Examples:
gamma(-2.5) # => -0.9453087204829431 gamma(-1.5) # => 2.3632718012073513 gamma(-0.5) # => -3.5449077018110375 gamma(0.0) # => Infinity gamma(1.0) # => 1.0 gamma(2.0) # => 1.0 gamma(3.0) # => 2.0 gamma(4.0) # => 6.0 gamma(5.0) # => 24.0
Related: Math.lgamma.
Returns a 2-element array equivalent to:
[Math.log(Math.gamma(x).abs), Math.gamma(x) < 0 ? -1 : 1]
See logarithmic gamma function.
Domain: (-INFINITY, INFINITY].
Range of first element: (-INFINITY, INFINITY].
Second element is -1 or 1.
Examples:
lgamma(-4.0) # => [Infinity, -1] lgamma(-3.0) # => [Infinity, -1] lgamma(-2.0) # => [Infinity, -1] lgamma(-1.0) # => [Infinity, -1] lgamma(0.0) # => [Infinity, 1] lgamma(1.0) # => [0.0, 1] lgamma(2.0) # => [0.0, 1] lgamma(3.0) # => [0.6931471805599436, 1] lgamma(4.0) # => [1.7917594692280545, 1] lgamma(-2.5) # => [-0.05624371649767279, -1] lgamma(-1.5) # => [0.8600470153764797, 1] lgamma(-0.5) # => [1.265512123484647, -1] lgamma(0.5) # => [0.5723649429247004, 1] lgamma(1.5) # => [-0.12078223763524676, 1] lgamma(2.5) # => [0.2846828704729205, 1]
Related: Math.gamma.
Some operating systems retain the status of terminated child processes until the parent collects that status (normally using some variant of wait()). If the parent never collects this status, the child stays around as a zombie process. Process::detach prevents this by setting up a separate Ruby thread whose sole job is to reap the status of the process pid when it terminates. Use detach only when you do not intend to explicitly wait for the child to terminate.
The waiting thread returns the exit status of the detached process when it terminates, so you can use Thread#join to know the result. If specified pid is not a valid child process ID, the thread returns nil immediately.
The waiting thread has pid method which returns the pid.
In this first example, we don’t reap the first child process, so it appears as a zombie in the process status display.
p1 = fork { sleep 0.1 } p2 = fork { sleep 0.2 } Process.waitpid(p2) sleep 2 system("ps -ho pid,state -p #{p1}")
produces:
27389 Z
In the next example, Process::detach is used to reap the child automatically.
p1 = fork { sleep 0.1 } p2 = fork { sleep 0.2 } Process.detach(p1) Process.waitpid(p2) sleep 2 system("ps -ho pid,state -p #{p1}")
(produces no output)
Returns the maximum number of GIDs allowed in the supplemental group access list.
Process.maxgroups #=> 32
Sets the maximum number of GIDs allowed in the supplemental group access list.