Class: Shell

Inherits:
Object
  • Object
show all
Extended by:
Exception2MessageMapper, Forwardable
Includes:
Error
Defined in:
lib/shell.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 “TESTn” # 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 “TESTn” 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 collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(pwd = Dir.pwd, umask = nil) ⇒ Shell

call-seq:

Shell.new(pwd, umask) -> obj

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



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# File 'lib/shell.rb', line 182

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 ⇒ Object

Returns the value of attribute cascade



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# File 'lib/shell.rb', line 107

def cascade
  @cascade
end

.debug ⇒ Object Also known as: debug?

Returns the value of attribute debug



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# File 'lib/shell.rb', line 107

def debug
  @debug
end

.verbose ⇒ Object Also known as: verbose?

Returns the value of attribute verbose



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# File 'lib/shell.rb', line 107

def verbose
  @verbose
end

Instance Attribute Details

#command_processor ⇒ Object (readonly)

Returns the value of attribute command_processor



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

def command_processor
  @command_processor
end

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

Returns the current working directory.



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# File 'lib/shell.rb', line 242

def cwd
  @cwd
end

#debug ⇒ Object Also known as: debug?

Returns the value of attribute debug



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

def debug
  @debug
end

#dir_stack ⇒ Object (readonly) Also known as: dirs

Returns the value of attribute dir_stack



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

def dir_stack
  @dir_stack
end

#process_controller ⇒ Object (readonly)

Returns the value of attribute process_controller



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

def process_controller
  @process_controller
end

#record_separator ⇒ Object

Returns the value of attribute record_separator



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# File 'lib/shell.rb', line 211

def record_separator
  @record_separator
end

#system_path ⇒ Object

Returns the command search path in an array



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# File 'lib/shell.rb', line 198

def system_path
  @system_path
end

#umask ⇒ Object

Returns the umask



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# File 'lib/shell.rb', line 210

def umask
  @umask
end

#verbose ⇒ Object Also known as: verbose?

Returns the value of attribute verbose



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

def verbose
  @verbose
end

Class Method Details

.alias_command(ali, command, *opts, &block) ⇒ Object

call-seq:

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

Convenience method for Shell::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



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# File 'lib/shell.rb', line 391

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

.cd(path) ⇒ Object

call-seq:

Shell.cd(path)

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



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# File 'lib/shell.rb', line 124

def cd(path)
  new(path)
end

.def_system_command(command, path = command) ⇒ Object

call-seq:

def_system_command(command, path = command)

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



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# File 'lib/shell.rb', line 371

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

.default_record_separator ⇒ Object 



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# File 'lib/shell.rb', line 157

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

.default_record_separator=(rs) ⇒ Object 



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# File 'lib/shell.rb', line 165

def default_record_separator=(rs)
  @default_record_separator = rs
end

.default_system_path ⇒ Object

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"]



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# File 'lib/shell.rb', line 141

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

.default_system_path=(path) ⇒ Object

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.



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# File 'lib/shell.rb', line 153

def default_system_path=(path)
  @default_system_path = path
end

.install_system_commands(pre = "sys_") ⇒ Object

call-seq:

install_system_commands(pre = "sys_")

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

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



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# File 'lib/shell.rb', line 411

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

.notify(*opts) ⇒ Object 



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# File 'lib/shell.rb', line 424

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) ⇒ Object

Convenience method for Shell::CommandProcessor.unalias_command



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# File 'lib/shell.rb', line 396

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

.undef_system_command(command) ⇒ Object

Convenience method for Shell::CommandProcessor.undef_system_command



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# File 'lib/shell.rb', line 376

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

Instance Method Details

#chdir(path = nil, verbose = @verbose) ⇒ Object Also known as: cd

call-seq:

Shell.chdir(path)

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.



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# File 'lib/shell.rb', line 259

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

#expand_path(path) ⇒ Object 



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

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

#inspect ⇒ Object 



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# File 'lib/shell.rb', line 416

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

#jobs ⇒ Object

Returns a list of scheduled jobs.



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

def jobs
  @process_controller.jobs
end

#kill(sig, command) ⇒ Object

call-seq:

kill(signal, job)

Sends the given signal to the given job



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# File 'lib/shell.rb', line 351

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

#popdir ⇒ Object Also known as: popd

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



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# File 'lib/shell.rb', line 327

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

#pushdir(path = nil, verbose = @verbose) ⇒ Object Also known as: pushd

call-seq:

pushdir(path)
pushdir(path) { &block }

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.



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# File 'lib/shell.rb', line 293

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