Output not being displayed when using command line

NotionCommotion · 12-15-2015, 07:46 AM

I am using the BACnet stack at http://sourceforge.net/projects/bacnet/ on both a Centos box and a Raspberry Pi. Note that this question has nothing to do about BACnet or this library.

I perform an identical command on the two machines, and the Raspberry Pi displays a response, but the Centos box does not. I think that the Centos box might be directing the output to something other than stdout.

Any recommendations how to troubleshoot and get the Centos box to display the output? Thanks

Code:

pi@raspberrypi ~/bacnet-stack-0-8-0 $ ./bin/bacrp 1234 1 0 85
100.000000
pi@raspberrypi ~/bacnet-stack-0-8-0 $

Code:

[root@devserver bacnet-stack-0-8-0]# ./bin/bacrp 1234 1 0 85
[root@devserver bacnet-stack-0-8-0]#

grail · 12-15-2015, 11:16 AM

Quote:

Note that this question has nothing to do about BACnet or this library.

I feel this is a big call as the shell would not make up its own mind to change where to send something.

Is it possible that the arguments might yield different results depending on which machine they are run on?

From the website I found:

Code:

$ demo/readprop/bacrp
bacrp device-instance object-type object-instance property [index]

Surely the device-instance would need to be different?

thomas.hedden · 12-15-2015, 02:19 PM

I don't know the command or BACnet, but I did notice that one
command was issued as a normal user and the other was issued as root.
I wonder whether this command behaves differently for root that it does
for normal users? You might try logging in as root on the other machine
or vice-versa.
Tom

JJJCR · 12-15-2015, 11:04 PM

In addition to above replies, have you tried redirection to a file?

And check whether the file will have the output.

NotionCommotion · 12-16-2015, 02:12 PM

Thank you Grail, Thomas, and JJJCR,

Turns out it was an iptables issue. Iptables is allowing incoming communication to the Centos box but not outgoing communication (I don't think I even have a firewall on the Pi). I didn't state so on my original post, but I also have a server application being ran on both machines. The Pi client is able to access the server application on the Centos box using ./bin/bacrp 1234 1 0 85 which in turn is able to give a reply back (for some reason, this is allowed). But executing ./bin/bacrp 1234 1 0 85 on the Centos box gets blocked, so nothing is displayed.

Still trying to resolve it, and if you have any thoughts, please see http://www.linuxquestions.org/questi...73#post5465173