# Using popen with 0,1,2,3,4 streams **URL:** \ **Category:** Ruby\ **Created:** [December 2, 2007, 12:12pm UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888 "2007-12-02T12:12:39Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 2, 2007, 12:12pm UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/1 "2007-12-02T12:12:39Z")
Hi ! I try to run command system and get streams handlers to 0 (stdin), 1(stdout), 2(stderr), 3(myOwnStdIn1), 4(myOwnStdIn2). I do something like that in PHP by proc\_open and table of pipes, but here I don’t know how I can get handlers to process streams. I know that this code is bad but I think something like this: process = popen(‘command’, ‘w+’); stdin = process.new(0, “w”); stdout = process.new(1, “r”); etc… But new is a static method. What i should to do ? ---
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 4, 2007, 1:33am UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/2 "2007-12-04T01:33:52Z")
Jan, You might look at popen3 in the standard library. I don’t think it quite does what you need (since it returns an array if three pipes: stdin, stdout and stderr for the subprocess) but the code is short if a little arcane, and might point you in the right direction to figure this out. Judson ---
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 4, 2007, 6:22pm UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/3 "2007-12-04T18:22:50Z")
On Dec 3, 2007 5:32 PM, Judson L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On Dec 2, 2007 3:10 AM, Jan Koprowski [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > stdin = process.new(0, “w”); > > stdout = process.new(1, “r”); > > > > etc… > > > > But new is a static method. What i should to do ? Also take a look at open4 and systemu. You can find both at the codeforpeople project on RubyForge. They, too, will offer some good insight on what you want to do, though neither does precisely what you need. [http://rubyforge.org/projects/codeforpeople](http://rubyforge.org/projects/codeforpeople) Blessings, TwP ---
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 6, 2007, 9:27am UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/4 "2007-12-06T09:27:38Z")
On 4 Gru, 17:58, Tim P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > is bad but I think something like this: > > > codeforpeople project on RubyForge. They, too, will offer some good > > > insight on what you want to do, though neither does precisely what you > > > need. > > [http://rubyforge.org/projects/codeforpeople](http://rubyforge.org/projects/codeforpeople) > > Blessings, > TwP Thank You for respond. I know that I can use only 3 pipes. But I think I can look for open4 and try to write something similar. Thanks ! ---
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 6, 2007, 9:42am UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/5 "2007-12-06T09:42:16Z")
On 4 Gru, 17:58, Tim P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > is bad but I think something like this: > > > codeforpeople project on RubyForge. They, too, will offer some good > > > insight on what you want to do, though neither does precisely what you > > > need. > > [http://rubyforge.org/projects/codeforpeople](http://rubyforge.org/projects/codeforpeople) > > Blessings, > TwP U try to write something like this: # # To change this template, choose Tools | Templates # and open the template in the editor. require ‘fcntl’ require ‘timeout’ require ‘thread’ class Broker\_process3 READ = 0 # Consts to explicite mark read WRITE = 1 # and write pipes @stdin @stdout @stderr def initialize end def self.run (command, params) pw, pr, pe, pl, pp = IO.pipe, IO.pipe, IO.pipe, IO.pipe, IO.pipe pl.last.fcntl(Fcntl::F\_SETFD, Fcntl::FD\_CLOEXEC) pp.last.fcntl(Fcntl::F\_SETFD, Fcntl::FD\_CLOEXEC) ``` pid = fork { pw.last.close STDIN.reopen pw.first pw.first.close pr.first.close STDOUT.reopen pr.last pr.last.close pe.first.close STDERR.reopen pe.last pe.last.close pl.last.close pp.last.close STDOUT.sync = STDERR.sync = true exec(*command) } [pw.first, pr.last, pe.last, pl.first, pp.first].each{|fd| ``` fd.close} ``` pl.last.write("login"); // ERROR HERE pl.last.close pp.last.write("has³o"); pp.last.close pw.last.close out = pr.first.readlines pr.first.close pe.first.close puts out; ``` end end but in // ERROR HERE I get: ./broker\_process3.rb:48:in `write': Broken pipe (Errno::EPIPE) from ./broker_process3.rb:48:in `run’ from /home/johny/NetBeansProjects/zhradmin/lib/main.rb:12 ---
**Author:** ![Jan\_Koprowski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/c5a1d2/32.png) [@Jan\_Koprowski](https://www.ruby-forum.com/u/Jan_Koprowski)\ **Post date:** [December 6, 2007, 9:43am UTC](https://www.ruby-forum.com/t/using-popen-with-0-1-2-3-4-streams/121888/6 "2007-12-06T09:43:27Z")
On 4 Gru, 17:58, Tim P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > is bad but I think something like this: > > > codeforpeople project on RubyForge. They, too, will offer some good > > > insight on what you want to do, though neither does precisely what you > > > need. > > [http://rubyforge.org/projects/codeforpeople](http://rubyforge.org/projects/codeforpeople) > > Blessings, > TwP U try to write something like this: # # To change this template, choose Tools | Templates # and open the template in the editor. require ‘fcntl’ require ‘timeout’ require ‘thread’ class Broker\_process3 READ = 0 # Consts to explicite mark read WRITE = 1 # and write pipes @stdin @stdout @stderr def initialize end def self.run (command, params) pw, pr, pe, pl, pp = IO.pipe, IO.pipe, IO.pipe, IO.pipe, IO.pipe pl.last.fcntl(Fcntl::F\_SETFD, Fcntl::FD\_CLOEXEC) pp.last.fcntl(Fcntl::F\_SETFD, Fcntl::FD\_CLOEXEC) ``` pid = fork { pw.last.close STDIN.reopen pw.first pw.first.close pr.first.close STDOUT.reopen pr.last pr.last.close pe.first.close STDERR.reopen pe.last pe.last.close pl.last.close pp.last.close STDOUT.sync = STDERR.sync = true exec(*command) } [pw.first, pr.last, pe.last, pl.first, pp.first].each{|fd| ``` fd.close} ``` pl.last.write("login"); // ERROR HERE pl.last.close pp.last.write("has³o"); pp.last.close pw.last.close out = pr.first.readlines pr.first.close pe.first.close puts out; ``` end end but in // ERROR HERE I get: ./broker\_process3.rb:48:in `write': Broken pipe (Errno::EPIPE) from ./broker_process3.rb:48:in `run’ from /home/johny/NetBeansProjects/zhradmin/lib/main.rb:12