QNX Operating System/Discussion/OSTech/fesh,esh output redirection problem/List of Posts
 
Forum Topic - fesh,esh output redirection problem:
   
Update
Michael Tasche
09/30/2010 8:14 AM
post69139
fesh,esh output redirection problem   
Hello all,

"eecho Teststring >testfile" results in an empty file and the output string is printed to the console.

All (f)esh buildin commands seems to behave like this.
If you start a normal process from the embedded shell, redirection works as expected.

Is this a bug or a feature?

-Michael
Gervais Mulongoy
09/30/2010 8:28 AM
post69142
Re: fesh,esh output redirection problem   
See http://www.qnx.com/developers/docs/6.4.1/neutrino/utilities/f/fesh.html#eecho

It is a feature. Use regular echo if you want the other behavior.

Michael Tasche <community-noreply@qnx.com> wrote:

Hello all,

"eecho Teststring >testfile" results in an empty file and the output string is printed to the console.

All (f)esh buildin commands seems to behave like this.
If you start a normal process from the embedded shell, redirection works as expected.

Is this a bug or a feature?

-Michael






_______________________________________________

OSTech
http://community.qnx.com/sf/go/post69139
Michael Tasche
09/30/2010 10:49 AM
post69180
Re: fesh,esh output redirection problem   
> See http://www.qnx.com/developers/docs/6.4.1/neutrino/utilities/f/fesh.html#
> eecho
> 
> It is a feature. Use regular echo if you want the other behavior.

Well, I am fighting against a very small nor flash.

Other example: 
# alias walter=uwe
# alias >testfile
walter=uwe

=> Output goes to console.
=> The file "testfile" is created, but empty.
For what we need this feature?
Perhaps you can explain that.

BTW:The "alias" example works as expected with the kornshell.

-Michael
Gervais Mulongoy
09/30/2010 11:22 AM
post69184
Re: fesh,esh output redirection problem   
 Currently neither esh/fesh support redirection for print/eecho or the
alias command.

Prior to performing file globbing if the command parser detects either
the '>' or '<' redirection symbols in the command line it either creates
an empty file for writing or attempts to open one to read from. This
explains the behavior you have observed so far.

While I know this doesn't quite answer your question as to why things
are like this but if we keep in mind that redirection is not supported
for those commands then adding redirection symbols in the command line
can be classified as unspecified behavior. Redirection support can be
added to those commands with relative ease though.

The Korn shell is a different shell and also was not designed with the
same requirements as either esh/fesh so not valid for the comparison.

On 09/30/10 10:49, Michael Tasche wrote:
>> See http://www.qnx.com/developers/docs/6.4.1/neutrino/utilities/f/fesh.html#
>> eecho
>>
>> It is a feature. Use regular echo if you want the other behavior.
> Well, I am fighting against a very small nor flash.
>
> Other example: 
> # alias walter=uwe
> # alias >testfile
> walter=uwe
>
> => Output goes to console.
> => The file "testfile" is created, but empty.
> For what we need this feature?
> Perhaps you can explain that.
>
> BTW:The "alias" example works as expected with the kornshell.
>
> -Michael
>
>
>
> _______________________________________________
>
> OSTech
> http://community.qnx.com/sf/go/post69180
>
Michael Tasche
10/01/2010 6:10 AM
post69235
Re: fesh,esh output redirection problem   
> 
>  Currently neither esh/fesh support redirection for print/eecho or the
> alias command.
> 
> Prior to performing file globbing if the command parser detects either
> the '>' or '<' redirection symbols in the command line it either creates
> an empty file for writing or attempts to open one to read from. This
> explains the behavior you have observed so far.
> 
> While I know this doesn't quite answer your question as to why things
> are like this but if we keep in mind that redirection is not supported
> for those commands then adding redirection symbols in the command line
> can be classified as unspecified behavior. Redirection support can be
> added to those commands with relative ease though.

Yes, I agree after looking at the esh source.
At the moment the "redirection feature for buildin commands" is not mission critical for my project, but I think this 
feature would be very senseful for the embedded shell.

What do you think?
Gervais Mulongoy
10/01/2010 9:22 AM
post69256
Re: fesh,esh output redirection problem   
You are certainly free to add redirection support as the source code is available. I provide a rough diff that adds 
support to most commands - you are free to use this but remember this is not a supported customization.
Attachment: Text esh.diff 3.24 KB
Attilla Danko(deleted)
09/30/2010 10:28 AM
post69168
RE: fesh,esh output redirection problem   
esh redirection works correctly for me in 6.5.0 M9: 

#esh
#echo "this is good" >good.txt 
#cat good.txt
this is good



>"eecho

I'm assuming you meant to write "echo" with one e.

-ad


-----Original Message-----
From: Michael Tasche [mailto:community-noreply@qnx.com]
Sent: Thu 2010-09-30 08:14
To: ostech-core_os
Subject: fesh,esh output redirection problem
 
Hello all,

"eecho Teststring >testfile" results in an empty file and the output string is printed to the console.

All (f)esh buildin commands seems to behave like this.
If you start a normal process from the embedded shell, redirection works as expected.

Is this a bug or a feature?

-Michael






_______________________________________________

OSTech
http://community.qnx.com/sf/go/post69139
Attachment: Text winmail.dat 2.77 KB
Neil Schellenberger(deleted)
09/30/2010 10:32 AM
post69171
RE: fesh,esh output redirection problem   
Actually, eecho is a fesh built-in.  Whether the behaviour is expected
or not, I'm not certain.

On Thu, 2010-09-30 at 10:28 -0400, Attilla Danko wrote:
> esh redirection works correctly for me in 6.5.0 M9:
> 
> #esh
> #echo "this is good" >good.txt
> #cat good.txt
> this is good
> 
> 
> 
> >"eecho
> 
> I'm assuming you meant to write "echo" with one e.
> 
> -ad
> 
> 
> -----Original Message-----
> From: Michael Tasche [mailto:community-noreply@qnx.com]
> Sent: Thu 2010-09-30 08:14
> To: ostech-core_os
> Subject: fesh,esh output redirection problem
> 
> Hello all,
> 
> "eecho Teststring >testfile" results in an empty file and the output
> string is printed to the console.
> 
> All (f)esh buildin commands seems to behave like this.
> If you start a normal process from the embedded shell, redirection
> works as expected.
> 
> Is this a bug or a feature?
> 
> -Michael
> 
> 
> 
> 
> 
> 
> _______________________________________________
> 
> OSTech
> http://community.qnx.com/sf/go/post69139
> 
> 
> 
> 
> 
> 
> _______________________________________________
> 
> OSTech
> http://community.qnx.com/sf/go/post69168
> 
>
Gervais Mulongoy
09/30/2010 10:44 AM
post69176
RE: fesh,esh output redirection problem   
Redirect support is not enabled for either print or eecho. 

Attilla Danko <community-noreply@qnx.com> wrote:

esh redirection works correctly for me in 6.5.0 M9: 

#esh
#echo "this is good" >good.txt 
#cat good.txt
this is good



>"eecho

I'm assuming you meant to write "echo" with one e.

-ad


-----Original Message-----
From: Michael Tasche [mailto:community-noreply@qnx.com]
Sent: Thu 2010-09-30 08:14
To: ostech-core_os
Subject: fesh,esh output redirection problem
 
Hello all,

"eecho Teststring >testfile" results in an empty file and the output string is printed to the console.

All (f)esh buildin commands seems to behave like this.
If you start a normal process from the embedded shell, redirection works as expected.

Is this a bug or a feature?

-Michael






_______________________________________________

OSTech
http://community.qnx.com/sf/go/post69139






_______________________________________________

OSTech
http://community.qnx.com/sf/go/post69168

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