# A few things about system and IO.popen - what's the current status? **URL:** \ **Category:** IronRuby\ **Created:** [March 4, 2009, 1:08pm UTC](https://www.ruby-forum.com/t/a-few-things-about-system-and-io-popen-whats-the-current-status/161977 "2009-03-04T13:08:35Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 4, 2009, 1:08pm UTC](https://www.ruby-forum.com/t/a-few-things-about-system-and-io-popen-whats-the-current-status/161977/1 "2009-03-04T13:08:35Z")
Hi, sorry if it’s a know fact - I could not find the info easily. I hope this will be useful. On Windows, system() seems to work partially, is it normal ? The following works: > > > system(“echo hello”) > > > hello > > > =\> true the following doesn’t seem to (although svn is in the path): > > > system(“svn”) > > > =\> false > > > > system(“svn.exe”) > > > =\> false Still on Windows, it seems that IO.popen crashes (I had a quick look at IoOps.cs to see if it was implemented): > > > IO.popen(“svn.exe”) do |io| puts io.read end > > > :0:in `popen': La référence d'objet n'est pas définie à une instance d'un objet. (System::NullReferenceException) from :0:in`popen’ > > > from :0 I ran the same stuff on Mono and got: IronRuby 1.0.0.0 on Mono 2.4 Copyright © Microsoft Corporation. All rights reserved. > > > system(“blah”) > > > IronRuby.Libraries:0:in `ExecuteProcessAndWait': No such file or directory (Errno::ENOENT) from IronRuby.Libraries:0:in`ExecuteCommandInShell’ > > > from :0:in `system’ > > > system(“svn”) > > > =\> nil > > > > system(“svn \> svninfo.txt”) > > > =\> nil > > > > exit Finally, running IO.popen on Mono gives the same output as Windows: IronRuby 1.0.0.0 on Mono 2.4 Copyright © Microsoft Corporation. All rights reserved. > > > IO.popen(“svn.exe”) { |io| puts io.read } > > > :0:in `popen': Object reference not set to an instance of an object (System::NullReferenceException) from :0:in`popen’ So my question is: what’s the current status on system and IO.popen ? Is it supposed to work and is it a regression, or is it not fully implemented ? I may be able to help at some point here (either by providing patches or testing on Mono + Windows) if it’s not your top priority 🙂 Given that I use Ruby to glue things together quite a lot, that would be useful to me. cheers, – Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 4, 2009, 5:42pm UTC](https://www.ruby-forum.com/t/a-few-things-about-system-and-io-popen-whats-the-current-status/161977/2 "2009-03-04T17:42:56Z")
Implementations of both “system” and “popen” are not solid. Any help here is very much appreciated! Feel free to submit patches and also new specs for these methods. Let us know if you need some changes in runtime (IronRuby.dll) since this assembly is not open to contributions just yet (but we might be able to factor some stuff out to libraries or provide the necessary functionality needed in core). BTW, our tag file for Kernel#system contains this suppressions: fails:Kernel#system can run basic things that exist fails:Kernel#system returns false when it can’t fails:Kernel#system does not write to stderr when it can’t find a command fails:Kernel#system uses /bin/sh if freaky shit is in the command fails:Kernel#system is a private method fails:Kernel#system expands shell variables when given a single string argument fails:Kernel#system does not expand shell variables when given multiples arguments Tomas From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Thibaut Barrère Sent: Wednesday, March 04, 2009 3:37 AM To: ironruby-core Subject: [Ironruby-core] A few things about system and IO.popen - what’s the current status ? Hi, sorry if it’s a know fact - I could not find the info easily. I hope this will be useful. On Windows, system() seems to work partially, is it normal ? The following works: > > > system(“echo hello”) > > > hello > > > =\> true the following doesn’t seem to (although svn is in the path): > > > system(“svn”) > > > =\> false > > > system(“svn.exe”) > > > =\> false Still on Windows, it seems that IO.popen crashes (I had a quick look at IoOps.cs to see if it was implemented): > > > IO.popen(“svn.exe”) do |io| puts io.read end > > > :0:in `popen': La référence d'objet n'est pas définie à une instance d'un objet. (System::NullReferenceException) from :0:in `popen’ > > > from :0 I ran the same stuff on Mono and got: IronRuby 1.0.0.0 on Mono 2.4 Copyright (c) Microsoft Corporation. All rights reserved. > > > system(“blah”) > > > IronRuby.Libraries:0:in `ExecuteProcessAndWait': No such file or directory (Errno::ENOENT) from IronRuby.Libraries:0:in `ExecuteCommandInShell’ > > > from :0:in `system’ > > > system(“svn”) > > > =\> nil > > > system(“svn \> svninfo.txt”) > > > =\> nil > > > exit Finally, running IO.popen on Mono gives the same output as Windows: IronRuby 1.0.0.0 on Mono 2.4 Copyright (c) Microsoft Corporation. All rights reserved. > > > IO.popen(“svn.exe”) { |io| puts io.read } > > > :0:in `popen': Object reference not set to an instance of an object (System::NullReferenceException) from :0:in `popen’ So my question is: what’s the current status on system and IO.popen ? Is it supposed to work and is it a regression, or is it not fully implemented ? I may be able to help at some point here (either by providing patches or testing on Mono + Windows) if it’s not your top priority 🙂 Given that I use Ruby to glue things together quite a lot, that would be useful to me. cheers, – Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 4, 2009, 6:24pm UTC](https://www.ruby-forum.com/t/a-few-things-about-system-and-io-popen-whats-the-current-status/161977/3 "2009-03-04T18:24:03Z")
I don’t know how the semantics differ from Ruby’s, but someone interested in doing this could probably adapt the IronPython source code. These functions should be in “nt.cs”. 🙂 From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Tomas M. Sent: Wednesday, March 04, 2009 8:42 AM To: removed\_email\_address@domain.invalid Subject: Re: [Ironruby-core] A few things about system and IO.popen - what’s the current status ? Implementations of both “system” and “popen” are not solid. Any help here is very much appreciated! Feel free to submit patches and also new specs for these methods. Let us know if you need some changes in runtime (IronRuby.dll) since this assembly is not open to contributions just yet (but we might be able to factor some stuff out to libraries or provide the necessary functionality needed in core). BTW, our tag file for Kernel#system contains this suppressions: fails:Kernel#system can run basic things that exist fails:Kernel#system returns false when it can’t fails:Kernel#system does not write to stderr when it can’t find a command fails:Kernel#system uses /bin/sh if freaky shit is in the command fails:Kernel#system is a private method fails:Kernel#system expands shell variables when given a single string argument fails:Kernel#system does not expand shell variables when given multiples arguments Tomas From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Thibaut Barrère Sent: Wednesday, March 04, 2009 3:37 AM To: ironruby-core Subject: [Ironruby-core] A few things about system and IO.popen - what’s the current status ? Hi, sorry if it’s a know fact - I could not find the info easily. I hope this will be useful. On Windows, system() seems to work partially, is it normal ? The following works: > > > system(“echo hello”) > > > hello > > > =\> true the following doesn’t seem to (although svn is in the path): > > > system(“svn”) > > > =\> false > > > system(“svn.exe”) > > > =\> false Still on Windows, it seems that IO.popen crashes (I had a quick look at IoOps.cs to see if it was implemented): > > > IO.popen(“svn.exe”) do |io| puts io.read end > > > :0:in `popen': La référence d'objet n'est pas définie à une instance d'un objet. (System::NullReferenceException) from :0:in `popen’ > > > from :0 I ran the same stuff on Mono and got: IronRuby 1.0.0.0 on Mono 2.4 Copyright (c) Microsoft Corporation. All rights reserved. > > > system(“blah”) > > > IronRuby.Libraries:0:in `ExecuteProcessAndWait': No such file or directory (Errno::ENOENT) from IronRuby.Libraries:0:in `ExecuteCommandInShell’ > > > from :0:in `system’ > > > system(“svn”) > > > =\> nil > > > system(“svn \> svninfo.txt”) > > > =\> nil > > > exit Finally, running IO.popen on Mono gives the same output as Windows: IronRuby 1.0.0.0 on Mono 2.4 Copyright (c) Microsoft Corporation. All rights reserved. > > > IO.popen(“svn.exe”) { |io| puts io.read } > > > :0:in `popen': Object reference not set to an instance of an object (System::NullReferenceException) from :0:in `popen’ So my question is: what’s the current status on system and IO.popen ? Is it supposed to work and is it a regression, or is it not fully implemented ? I may be able to help at some point here (either by providing patches or testing on Mono + Windows) if it’s not your top priority 🙂 Given that I use Ruby to glue things together quite a lot, that would be useful to me. cheers, – Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 4, 2009, 10:17pm UTC](https://www.ruby-forum.com/t/a-few-things-about-system-and-io-popen-whats-the-current-status/161977/4 "2009-03-04T22:17:10Z")
Hi, thanks for the pointers. I’ll first have to learn how to compile and launch the specs on my machine. If I manage to get something useful, I’ll report back. cheers, – Thibaut