class Process

Defined in:

kernel.cr
process.cr:1
process.cr:14
process/executable_path.cr:5
process/executable_path.cr:94
process/shell.cr

Constant Summary

PATH_DELIMITER = {% if flag?(:windows) %} ';' {% else %} ':' {% end %}

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil) same?, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.new(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = false, input : Stdio = Redirect::Close, output : Stdio = Redirect::Close, error : Stdio = Redirect::Close, chdir : String? = nil)Source

Creates a process, executes it, but doesn't wait for it to complete.

To wait for it to finish, invoke #wait.

By default the process is configured without input, output or error.

If shell is false, the command is the path to the executable to run, along with a list of args.

If shell is true, the command should be the full command line including space-separated args.

  • On POSIX this uses /bin/sh to process the command string. args are also passed to the shell, and you need to include the string "${@}" in the command to safely insert them there.
  • On Windows this is implemented by passing the string as-is to the process, and passing args is not supported.

Raises IO::Error if executing the command fails (for example if the executable doesn't exist).

Class Method Detail

def self.chroot(path : String) : NilSource

Changes the root directory and the current working directory for the current process.

Available only on Unix-like operating systems.

Security: .chroot on its own is not an effective means of mitigation. At minimum the process needs to also drop privileges as soon as feasible after the .chroot. Changes to the directory hierarchy or file descriptors passed via recvmsg(2) from outside the .chroot jail may allow a restricted process to escape, even if it is unprivileged.

Process.chroot("/var/empty")

def self.exec(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = false, input : ExecStdio = Redirect::Inherit, output : ExecStdio = Redirect::Inherit, error : ExecStdio = Redirect::Inherit, chdir : String? = nil) : NoReturnSource

Replaces the current process with a new one. This function never returns.

Available only on Unix-like operating systems.

Raises IO::Error if executing the command fails (for example if the executable doesn't exist).

def self.executable_path : String?Source

Returns an absolute path to the executable file of the currently running program. This is in opposition to PROGRAM_NAME which may be a relative or absolute path, just the executable file name or a symlink.

The executable path will be canonicalized (all symlinks and relative paths will be expanded).

Returns nil if the file can't be found.

def self.exists?(pid : Int) : BoolSource

Returns true if the process identified by pid is valid for a currently registered process, false otherwise. Note that this returns true for a process in the zombie or similar state.

def self.exit(status = 0) : NoReturnSource

Terminate the current process immediately. All open files, pipes and sockets are flushed and closed, all child processes are inherited by PID 1. This does not run any handlers registered with at_exit, use ::exit for that.

status is the exit status of the current process.

def self.find_executable(name : Path | String, path : String? = ENV["PATH"]?, pwd : Path | String = Dir.current) : String?Source

Searches an executable, checking for an absolute path, a path relative to pwd or absolute path, then eventually searching in directories declared in path.

def self.parse_arguments(line : String) : Array(String)Source

Split a line string into the array of tokens in the same way the POSIX shell.

Process.parse_arguments(%q["foo bar" '\hello/' Fizz\ Buzz]) # => ["foo bar", "\\hello/", "Fizz Buzz"]

See https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_03

def self.pgid(pid : Int) : Int64Source

Returns the process group identifier of the process identified by pid.

def self.pgid : Int64Source

Returns the process group identifier of the current process.

def self.pid : Int64Source

Returns the process identifier of the current process.

def self.ppid : Int64Source

Returns the process identifier of the parent process of the current process.

def self.quote(args : Enumerable(String)) : StringSource

Converts a sequence of strings to one joined string with each argument shell-quoted.

This is then safe to pass as part of the command when using shell: true or system().

NOTE The actual return value is system-dependent, so it mustn't be relied on in other contexts. See also: .quote_posix.

files = ["my file.txt", "another.txt"]
`grep -E 'fo+' -- #{Process.quote(files)}`

def self.quote(arg : String) : StringSource

Shell-quotes one item, same as .quote({arg}).

def self.quote_posix(args : Enumerable(String)) : StringSource

Converts a sequence of strings to one joined string with each argument shell-quoted.

This is then safe to pass to a POSIX shell.

files = ["my file.txt", "another.txt"]
Process.quote_posix(files) # => "'my file.txt' another.txt"

def self.quote_posix(arg : String) : StringSource

Shell-quotes one item, same as .quote_posix({arg}).

def self.run(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = false, input : Stdio = Redirect::Close, output : Stdio = Redirect::Close, error : Stdio = Redirect::Close, chdir : String? = nil) : Process::StatusSource

Executes a process and waits for it to complete.

By default the process is configured without input, output or error.

Raises IO::Error if executing the command fails (for example if the executable doesn't exist).

def self.run(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = false, input : Stdio = Redirect::Pipe, output : Stdio = Redirect::Pipe, error : Stdio = Redirect::Pipe, chdir : String? = nil, &)Source

Executes a process, yields the block, and then waits for it to finish.

By default the process is configured to use pipes for input, output and error. These will be closed automatically at the end of the block.

Returns the block's value.

Raises IO::Error if executing the command fails (for example if the executable doesn't exist).

def self.signal(signal : Signal, pid : Int) : NilSource

Sends signal to the process identified by pid.

def self.times : TmsSource

Returns a Tms for the current process. For the children times, only those of terminated children are returned on Unix; they are zero on Windows.

Instance Method Detail

def close : NilSource

Closes any system resources (e.g. pipes) held for the child process.

def error : IO::FileDescriptorSource

A pipe to this process' error. Raises if a pipe wasn't asked when creating the process.

def error? : IO::FileDescriptor?Source

A pipe to this process' error. Raises if a pipe wasn't asked when creating the process.

def exists? : BoolSource

Whether the process is still registered in the system. Note that this returns true for processes in the zombie or similar state.

def finalizeSource

def input : IO::FileDescriptorSource

A pipe to this process' input. Raises if a pipe wasn't asked when creating the process.

def input? : IO::FileDescriptor?Source

A pipe to this process' input. Raises if a pipe wasn't asked when creating the process.

def output : IO::FileDescriptorSource

A pipe to this process' output. Raises if a pipe wasn't asked when creating the process.

def output? : IO::FileDescriptor?Source

A pipe to this process' output. Raises if a pipe wasn't asked when creating the process.

def pid : Int64Source

Returns the process identifier of this process.

def signal(signal : Signal) : NilSource

Sends signal to this process.

def terminate : NilSource

Asks this process to terminate gracefully

def terminated? : BoolSource

Whether this process is already terminated.

def wait : Process::StatusSource

Waits for this process to complete and closes any pipes.

© 2012–2021 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/1.2.1/Process.html