Module: Syscmd

Defined in:
lib/syscmd.rb,
lib/syscmd/popen.rb

Overview

Module.

Defined Under Namespace

Classes: AlreadyExecutedError, Command

Class Method Summary collapse

Class Method Details

.exec!(cmd, *args) ⇒ Object

execute a system command.

cmd

the command to execute

args

command line arguments

returns

executed Syscmd::Command object



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# File 'lib/syscmd.rb', line 104

def exec!(cmd, *args)
  cmd = Command.new(cmd, args)
  cmd.exec!
end

.popen(*cmd) ⇒ Object

Taken from the original Ruby 1.8 implementation of Open3::open3 and slightly tweaked to return an exit status. This function is meant as in internal method of the Syscmd module; do not use it on it’s own, as the interface may change anytime.

cmd

the command to execute

returns

status, stdout, stderr

orignal author

Yukihiro Matsumoto

orignal socumentation

Konrad Meyer



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# File 'lib/syscmd/popen.rb', line 12

def popen(*cmd)
  pw = IO::pipe   # pipe[0] for read, pipe[1] for write
  pr = IO::pipe
  pe = IO::pipe
  status = 0 # status of the inner fork

  pid = fork do
    # child
    gcpid = fork do
    	# grandchild
    	pw[1].close
    	STDIN.reopen(pw[0])
    	pw[0].close

    	pr[0].close
    	STDOUT.reopen(pr[1])
    	pr[1].close

    	pe[0].close
    	STDERR.reopen(pe[1])
    	pe[1].close

    	exec(*cmd)
    end
    gcpid, gcstatus = Process.wait2(gcpid)
    exit!(gcstatus.exitstatus)
  end

  pw[0].close
  pr[1].close
  pe[1].close
  pid, status = Process.wait2(pid)
  
  #pi = [status.exitstatus, pw[1], pr[0], pe[0]]
  pi = [status, pr[0], pe[0]]
  pw[1].sync = true
  if defined? yield
    begin
     return yield(*pi)
    ensure
     pi.each{|p| p.close unless p.closed?}
    end
  end
  pi
end