Class: Shell

Relationships & Source Files
Namespace Children
Modules: Error
Classes: AppendFile, AppendIO, BuiltInCommand, Cat, CommandProcessor, Concat, Echo, Filter, Glob, ProcessController, SystemCommand, Tee, Void
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, Forwardable, Exception2MessageMapper
Instance Chain: self, Error
Inherits:	Object
Defined in:	lib/shell.rb, lib/shell/builtin-command.rb, lib/shell/command-processor.rb, lib/shell/error.rb, lib/shell/filter.rb, lib/shell/process-controller.rb, lib/shell/system-command.rb, lib/shell/version.rb

Overview

Shell implements an idiomatic Ruby interface for common UNIX shell commands.

It provides users the ability to execute commands with filters and pipes, like sh/csh by using native facilities of Ruby.

Examples

Temp file creation

In this example we will create three tmpFile's in three different folders under the /tmp directory.

sh = Shell.cd("/tmp") # Change to the /tmp directory
sh.mkdir "shell-test-1" unless sh.exists?("shell-test-1")
# make the 'shell-test-1' directory if it doesn't already exist
sh.cd("shell-test-1") # Change to the /tmp/shell-test-1 directory
for dir in ["dir1", "dir3", "dir5"]
  if !sh.exists?(dir)
    sh.mkdir dir # make dir if it doesn't already exist
    sh.cd(dir) do
      # change to the `dir` directory
    f = sh.open("tmpFile", "w") # open a new file in write mode
    f.print "TEST\n"            # write to the file
    f.close                     # close the file handler
    end
    print sh.pwd                  # output the process working directory
  end
end

Temp file creation with self

This example is identical to the first, except we're using CommandProcessor#transact.

CommandProcessor#transact executes the given block against self, in this case sh; our Shell object. Within the block we can substitute sh.cd to .cd, because the scope within the block uses sh already.

sh = Shell.cd("/tmp")
sh.transact do
  mkdir "shell-test-1" unless exists?("shell-test-1")
  cd("shell-test-1")
  for dir in ["dir1", "dir3", "dir5"]
    if !exists?(dir)
    mkdir dir
    cd(dir) do
      f = open("tmpFile", "w")
      f.print "TEST\n"
      f.close
    end
    print pwd
    end
  end
end

Pipe /etc/printcap into a file

In this example we will read the operating system file /etc/printcap, generated by cupsd, and then output it to a new file relative to the #pwd of sh.

sh = Shell.new
sh.cat("/etc/printcap") | sh.tee("tee1") > "tee2"
(sh.cat < "/etc/printcap") | sh.tee("tee11") > "tee12"
sh.cat("/etc/printcap") | sh.tee("tee1") >> "tee2"
(sh.cat < "/etc/printcap") | sh.tee("tee11") >> "tee12"

Class Attribute Summary

.cascade rw
.debug=(val) rw
.debug? rw

Alias for .debug.
.default_record_separator rw
.default_record_separator=(rs) rw
.default_system_path rw

Returns the directories in the current shell's PATH environment variable as an array of directory names.
.default_system_path=(path) rw

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

Alias for .verbose.

Class Method Summary

.alias_command(alias, command, *opts, &block)

Convenience method for CommandProcessor.alias_command.
.cd(path)

Creates a new Shell instance with the current working directory set to path.
.debug (also: .debug?) rw
.def_system_command(command, path = command)

Convenience method for CommandProcessor.def_system_command.
.install_system_commands(pre = "sys_")

Convenience method for CommandProcessor.install_system_commands.
.new(pwd, umask) ⇒ Object constructor

Creates a Shell object which current directory is set to the process current directory, unless otherwise specified by the #pwd argument.
.notify(*opts)
.unalias_command(ali)

Convenience method for CommandProcessor.unalias_command
.undef_system_command(command)

Convenience method for CommandProcessor.undef_system_command
.verbose (also: .verbose?) rw

Instance Attribute Summary

#command_processor readonly
#cwd (also: #dir, #getwd, #pwd) readonly

Returns the current working directory.
#debug=(val) rw
#debug? rw

Alias for #debug.
#dir readonly

Alias for #cwd.
#dir_stack (also: #dirs) readonly
#dirs readonly

Alias for #dir_stack.
#getwd readonly

Alias for #cwd.
#process_controller readonly
#pwd readonly

Alias for #cwd.
#record_separator rw
#system_path rw

Returns the command search path in an array.
#system_path=(path) rw

Sets the system path (the Shell instance's PATH environment variable).
#umask rw

Returns the umask.
#verbose? rw

Alias for #verbose.

Instance Method Summary

#cd(path = nil, verbose = @verbose)

Alias for #chdir.
#chdir(path) (also: #cd)

Creates a Shell object which current directory is set to path.
#debug (also: #debug?) rw
#expand_path(path)
#inspect
#jobs

Returns a list of scheduled jobs.
#kill(signal, job)

Sends the given signal to the given job
#popd

Alias for #popdir.
#popdir (also: #popd)

Pops a directory from the directory stack, and sets the current directory to it.
#pushd(path = nil, verbose = @verbose)

Alias for #pushdir.
#pushdir(path) (also: #pushd)

Pushes the current directory to the directory stack, changing the current directory to path.
#verbose (also: #verbose?) rw

Constructor Details

.new(pwd, umask) ⇒ `Object`

Creates a Shell object which current directory is set to the process current directory, unless otherwise specified by the #pwd argument.

[ GitHub ]

# File 'lib/shell.rb', line 184


def initialize(pwd = Dir.pwd, umask = nil)
  @cwd = File.expand_path(pwd)
  @dir_stack = []
  @umask = umask

  @system_path = Shell.default_system_path
  @record_separator = Shell.default_record_separator

  @command_processor = CommandProcessor.new(self)
  @process_controller = ProcessController.new(self)

  @verbose = Shell.verbose
  @debug = Shell.debug
end

Class Attribute Details

.cascade (rw)

[ GitHub ]

# File 'lib/shell.rb', line 108


attr_accessor :cascade, :verbose

.debug=(val) (rw)

[ GitHub ]

# File 'lib/shell.rb', line 115


def debug=(val)
  @debug = val
  @verbose = val if val
end

.debug? (rw)

Alias for .debug.

[ GitHub ]

# File 'lib/shell.rb', line 111


alias debug? debug

.default_record_separator (rw)

[ GitHub ]

# File 'lib/shell.rb', line 159


def default_record_separator
  if @default_record_separator
    @default_record_separator
  else
    $/
  end
end

.default_record_separator=(rs) (rw)

[ GitHub ]

# File 'lib/shell.rb', line 167


def default_record_separator=(rs)
  @default_record_separator = rs
end

.default_system_path (rw)

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"]

[ GitHub ]

# File 'lib/shell.rb', line 143


def default_system_path
  if @default_system_path
    @default_system_path
  else
    ENV["PATH"].split(":")
  end
end

.default_system_path=(path) (rw)

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.

[ GitHub ]

# File 'lib/shell.rb', line 155


def default_system_path=(path)
  @default_system_path = path
end

.verbose? (rw)

Alias for .verbose.

[ GitHub ]

# File 'lib/shell.rb', line 112


alias verbose? verbose

Class Method Details

.alias_command(alias, command, *opts, &block)

Convenience method for CommandProcessor.alias_command. Defines an instance method which will execute a command under an alternative name.

Shell.def_system_command('date')
Shell.alias_command('date_in_utc', 'date', '-u')
Shell.new.date_in_utc # => Sat Jan 25 16:59:57 UTC 2014

[ GitHub ]

# File 'lib/shell.rb', line 394


def Shell.alias_command(ali, command, *opts, &block)
  CommandProcessor.alias_command(ali, command, *opts, &block)
end

.cd(path)

Creates a new Shell instance with the current working directory set to path.

[ GitHub ]

# File 'lib/shell.rb', line 126


def cd(path)
  new(path)
end

.debug (rw) Also known as: .debug?

[ GitHub ]

# File 'lib/shell.rb', line 109


attr_reader :debug

.def_system_command(command, path = command)

Convenience method for CommandProcessor.def_system_command. Defines an instance method which will execute the given shell command. If the executable is not in .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!"

[ GitHub ]

# File 'lib/shell.rb', line 374


def Shell.def_system_command(command, path = command)
  CommandProcessor.def_system_command(command, path)
end

.install_system_commands(pre = "sys_")

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

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

[ GitHub ]

# File 'lib/shell.rb', line 414


def Shell.install_system_commands(pre = "sys_")
  CommandProcessor.install_system_commands(pre)
end

.notify(*opts)

[ GitHub ]

# File 'lib/shell.rb', line 427


def self.notify(*opts)
  Shell::debug_output_synchronize do
    if opts[-1].kind_of?(String)
      yorn = verbose?
    else
      yorn = opts.pop
    end
    return unless yorn

    if @debug_display_thread_id
      if @debug_display_process_id
        prefix = "shell(##{Process.pid}:#{Thread.current.to_s.sub("Thread", "Th")}): "
      else
        prefix = "shell(#{Thread.current.to_s.sub("Thread", "Th")}): "
      end
    else
      prefix = "shell: "
    end
    _head = true
    STDERR.print opts.collect{|mes|
      mes = mes.dup
      yield mes if iterator?
      if _head
        _head = false
        prefix + mes
      else
        " "* prefix.size + mes
      end
    }.join("\n")+"\n"
  end
end

.unalias_command(ali)

Convenience method for CommandProcessor.unalias_command

[ GitHub ]

# File 'lib/shell.rb', line 399


def Shell.unalias_command(ali)
  CommandProcessor.unalias_command(ali)
end

.undef_system_command(command)

Convenience method for CommandProcessor.undef_system_command

[ GitHub ]

# File 'lib/shell.rb', line 379


def Shell.undef_system_command(command)
  CommandProcessor.undef_system_command(command)
end

.verbose (rw) Also known as: .verbose?

[ GitHub ]

# File 'lib/shell.rb', line 108


attr_accessor :cascade, :verbose

Instance Attribute Details

#command_processor (readonly)

[ GitHub ]

# File 'lib/shell.rb', line 225


attr_reader :command_processor

#cwd (readonly) Also known as: #dir, #getwd, #pwd

Returns the current working directory.

[ GitHub ]

# File 'lib/shell.rb', line 245


attr_reader :cwd

#debug=(val) (rw)

[ GitHub ]

# File 'lib/shell.rb', line 217


def debug=(val)
  @debug = val
  @verbose = val if val
end

#debug? (rw)

Alias for #debug.

[ GitHub ]

# File 'lib/shell.rb', line 223


alias debug? debug

#dir (readonly)

Alias for #cwd.

[ GitHub ]

# File 'lib/shell.rb', line 246


alias dir cwd

#dir_stack (readonly) Also known as: #dirs

[ GitHub ]

# File 'lib/shell.rb', line 250


attr_reader :dir_stack

#dirs (readonly)

Alias for #dir_stack.

[ GitHub ]

# File 'lib/shell.rb', line 251


alias dirs dir_stack

#getwd (readonly)

Alias for #cwd.

[ GitHub ]

# File 'lib/shell.rb', line 247


alias getwd cwd

#process_controller (readonly)

[ GitHub ]

# File 'lib/shell.rb', line 226


attr_reader :process_controller

#pwd (readonly)

Alias for #cwd.

[ GitHub ]

# File 'lib/shell.rb', line 248


alias pwd cwd

#record_separator (rw)

[ GitHub ]

# File 'lib/shell.rb', line 213


attr_accessor :record_separator

#system_path (rw)

Returns the command search path in an array

[ GitHub ]

# File 'lib/shell.rb', line 200


attr_reader :system_path

#system_path=(path) (rw)

Sets the system path (the Shell instance's PATH environment variable).

path should be an array of directory name strings.

[ GitHub ]

# File 'lib/shell.rb', line 205


def system_path=(path)
  @system_path = path
  rehash
end

#umask (rw)

Returns the umask

[ GitHub ]

# File 'lib/shell.rb', line 212


attr_accessor :umask

#verbose? (rw)

Alias for #verbose.

[ GitHub ]

# File 'lib/shell.rb', line 222


alias verbose? verbose

Instance Method Details

#cd(path = nil, verbose = @verbose)

Alias for #chdir.

[ GitHub ]

# File 'lib/shell.rb', line 283


alias cd chdir

#chdir(path) Also known as: #cd

Creates a Shell object which current directory is set to path.

If a block is given, it restores the current directory when the block ends.

If called as iterator, it restores the current directory when the block ends.

[ GitHub ]

# File 'lib/shell.rb', line 262


def chdir(path = nil, verbose = @verbose)
  check_point

  if iterator?
    notify("chdir(with block) #{path}") if verbose
    cwd_old = @cwd
    begin
      chdir(path, nil)
      yield
    ensure
      chdir(cwd_old, nil)
    end
  else
    notify("chdir #{path}") if verbose
    path = "~" unless path
    @cwd = expand_path(path)
    notify "current dir: #{@cwd}"
    rehash
    Void.new(self)
  end
end

#debug (rw) Also known as: #debug?

[ GitHub ]

# File 'lib/shell.rb', line 215


attr_reader :debug

#expand_path(path)

[ GitHub ]

# File 'lib/shell.rb', line 228


def expand_path(path)
  File.expand_path(path, @cwd)
end

#inspect

[ GitHub ]

# File 'lib/shell.rb', line 419


def inspect
  if debug.kind_of?(Integer) && debug > 2
    super
  else
    to_s
  end
end

#jobs

Returns a list of scheduled jobs.

[ GitHub ]

# File 'lib/shell.rb', line 346


def jobs
  @process_controller.jobs
end

#kill(signal, job)

Sends the given signal to the given job

[ GitHub ]

# File 'lib/shell.rb', line 354


def kill(sig, command)
  @process_controller.kill_job(sig, command)
end

#popd

Alias for #popdir.

[ GitHub ]

# File 'lib/shell.rb', line 343


alias popd popdir

#popdir Also known as: #popd

Pops a directory from the directory stack, and sets the current directory to it.

[ GitHub ]

# File 'lib/shell.rb', line 330


def popdir
  check_point

  notify("popdir")
  if pop = @dir_stack.pop
    chdir pop
    notify "dir stack: [#{@dir_stack.join ', '}]"
    self
  else
    Shell.Fail DirStackEmpty
  end
  Void.new(self)
end

#pushd(path = nil, verbose = @verbose)

Alias for #pushdir.

[ GitHub ]

# File 'lib/shell.rb', line 326


alias pushd pushdir

#pushdir(path) #pushdir(path)
Also known as: #pushd

Pushes the current directory to the directory stack, changing the current directory to path.

If path is omitted, it exchanges its current directory and the top of its directory stack.

If a block is given, it restores the current directory when the block ends.

[ GitHub ]

# File 'lib/shell.rb', line 296


def pushdir(path = nil, verbose = @verbose)
  check_point

  if iterator?
    notify("pushdir(with block) #{path}") if verbose
    pushdir(path, nil)
    begin
      yield
    ensure
      popdir
    end
  elsif path
    notify("pushdir #{path}") if verbose
    @dir_stack.push @cwd
    chdir(path, nil)
    notify "dir stack: [#{@dir_stack.join ', '}]"
    self
  else
    notify("pushdir") if verbose
    if pop = @dir_stack.pop
      @dir_stack.push @cwd
      chdir pop
      notify "dir stack: [#{@dir_stack.join ', '}]"
      self
    else
      Shell.Fail DirStackEmpty
    end
  end
  Void.new(self)
end

#verbose (rw) Also known as: #verbose?

[ GitHub ]

# File 'lib/shell.rb', line 214


attr_accessor :verbose

Class: Shell

Overview

Examples

Temp file creation

Temp file creation with self

Pipe /etc/printcap into a file

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(pwd, umask) ⇒ Object

Class Attribute Details

.cascade (rw)

.debug=(val) (rw)

.debug? (rw)

.default_record_separator (rw)

.default_record_separator=(rs) (rw)

.default_system_path (rw)

.default_system_path=(path) (rw)

.verbose? (rw)

Class Method Details

.alias_command(alias, command, *opts, &block)

.cd(path)

.debug (rw) Also known as: .debug?

.def_system_command(command, path = command)

.install_system_commands(pre = "sys_")

.notify(*opts)

.unalias_command(ali)

.undef_system_command(command)

.verbose (rw) Also known as: .verbose?

Instance Attribute Details

#command_processor (readonly)

#cwd (readonly) Also known as: #dir, #getwd, #pwd

#debug=(val) (rw)

#debug? (rw)

#dir (readonly)

#dir_stack (readonly) Also known as: #dirs

#dirs (readonly)

#getwd (readonly)

#process_controller (readonly)

#pwd (readonly)

#record_separator (rw)

#system_path (rw)

#system_path=(path) (rw)

#umask (rw)

#verbose? (rw)

Instance Method Details

#cd(path = nil, verbose = @verbose)

#chdir(path) Also known as: #cd

#debug (rw) Also known as: #debug?

#expand_path(path)

#inspect

#jobs

#kill(signal, job)

#popd

#popdir Also known as: #popd

#pushd(path = nil, verbose = @verbose)

#pushdir(path) #pushdir(path) Also known as: #pushd

#verbose (rw) Also known as: #verbose?

.new(pwd, umask) ⇒ `Object`

#pushdir(path) #pushdir(path)
Also known as: #pushd