Class: SysCmd::Command

Inherits:
Object
  • Object
show all
Defined in:
lib/sys_cmd.rb

Overview

An executable system command

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(command, options = {}) ⇒ Command

Returns a new instance of Command.



200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
 
# File 'lib/sys_cmd.rb', line 200

def initialize(command, options = {})
  if command.respond_to?(:shell)
    @command = command.command
    @shell = command.shell
    @stdin_data = command.stdin_data
  else
    @command = command
    @shell = Shell.new(options)
    @stdin_data = options[:stdin_data]
  end
  @output = nil
  @status = nil
  @error_output = nil
  @error = nil
end

Instance Attribute Details

#command ⇒ Object (readonly)

Returns the value of attribute command.



216
217
218
 
# File 'lib/sys_cmd.rb', line 216

def command
  @command
end

#error ⇒ Object (readonly)

Returns the value of attribute error.



216
217
218
 
# File 'lib/sys_cmd.rb', line 216

def error
  @error
end

#error_output ⇒ Object (readonly)

Returns the value of attribute error_output.



216
217
218
 
# File 'lib/sys_cmd.rb', line 216

def error_output
  @error_output
end

#output ⇒ Object (readonly)

Returns the value of attribute output.



216
217
218
 
# File 'lib/sys_cmd.rb', line 216

def output
  @output
end

#status ⇒ Object (readonly)

Returns the value of attribute status.



216
217
218
 
# File 'lib/sys_cmd.rb', line 216

def status
  @status
end

Instance Method Details

#error? ⇒ Boolean

did the command execution caused an exception?

Returns:

  • (Boolean) 


304
305
306
 
# File 'lib/sys_cmd.rb', line 304

def error?
  !@error.nil?
end

#run(options = {}) ⇒ Object

Execute the command.

By default the command is executed by a shell. In this case, unquoted arguments are interpreted by the shell, e.g.

SysCmd.command('echo $BASH').run # /bin/bash

When the :direct option is set to true, no shell is used and the command is directly executed; in this case unquoted arguments are not interpreted:

SysCmd.command('echo $BASH').run # $BASH

The exit status of the command is retained in the status attribute (and its numeric value in the status_value attribute).

The standard output of the command is captured and retained in the output attribute.

By default, the standar error output of the command is not captured, so it will be shown on the console unless redirected.

Standard error can be captured and interleaved with the standard output passing the option

error_output: :mix

Error output can be captured and keep separate inthe error_output attribute with this option:

error_output: :separate

The value returned is by defaut, like in Kernel#system, true if the command gives zero exit status, false for non zero exit status, and nil if command execution fails.

The :return option can be used to make this method return other attribute of the executed command.

The :stdin_data option can be used to pass a String as the command’s standar input.



260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
 
# File 'lib/sys_cmd.rb', line 260

def run(options = {})
  @output = @status = @error_output = @error = nil
  if options[:direct]
    command = @shell.split(@command)
  else
    command = [@command]
  end
  stdin_data = options[:stdin_data] || @stdin_data
  if stdin_data
    command << { stdin_data: stdin_data }
  end
  begin
    case options[:error_output]
    when :mix # mix stderr with stdout
      @output, @status = Open3.capture2e(*command)
    when :separate
      @output, @error_output, @status = Open3.capture3(*command)
    else # :console (do not capture stderr output)
      @output, @status = Open3.capture2(*command)
    end
  rescue => error
    @error = error.dup
  end
  case options[:return]
  when :status
    @status
  when :status_value
    status_value
  when :output
    @output
  when :error_output
    @error_output
  when :command
    self
  else
    @error ? nil : @status.success? ? true : false
  end
end

#status_value ⇒ Object 



299
300
301
 
# File 'lib/sys_cmd.rb', line 299

def status_value
  @status && @status.exitstatus
end

#success? ⇒ Boolean

did the command execute without error and returned a success status?

Returns:

  • (Boolean) 


309
310
311
 
# File 'lib/sys_cmd.rb', line 309

def success?
  !error? && @status.success?
end

#to_s ⇒ Object 



313
314
315
 
# File 'lib/sys_cmd.rb', line 313

def to_s
  command
end