Register forum user name Search FAQ

Gammon Forum

Notice: Any messages purporting to come from this site telling you that your password has expired, or that you need to verify your details, confirm your email, resolve issues, making threats, or asking for money, are spam. We do not email users with any such messages. If you have lost your password you can obtain a new one by using the password reset link.

Due to spam on this forum, all posts now need moderator approval.

 Entire forum ➜ MUSHclient ➜ Lua ➜ os.env not working as I expected on yun

os.env not working as I expected on yun

It is now over 60 days since the last post. This thread is closed.     Refresh page


Posted by Jantje   Belgium  (2 posts)  Bio
Date Thu 14 May 2015 06:05 PM (UTC)
Message
Hi Nick
As we discussed a long time ago I have been using lua on yun and lately I ported a ash script to lua.
The performance boost is huge!!! So me really happy.
However I bumped in a wierd thing. It seems that environment variables that have been created during on the command prompt before lua is started are not found by lua.

In the following dump DumpFile was created by running a script.

root@Marvin2:/www/cgi-bin/jantje# echo $DumpFile
/tmp/jantje/ttyATH0/dump.txt
root@Marvin2:/www/cgi-bin/jantje# lua
Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio (double int32)
> print(os.getenv("DumpFile"))
nil
> print(os.getenv("HOME"))
/root

As you can see from the log above the OS knows the environment variable DumpFile but Lua does not.

Can you help me out on this one?
Txs
Jantje
Top

Posted by Nick Gammon   Australia  (23,166 posts)  Bio   Forum Administrator
Date Reply #1 on Thu 14 May 2015 08:02 PM (UTC)
Message
Template:Arduino Please post Arduino-related questions to the Arduino Forum or to StackExchange: Arduino. This saves splitting questions and answers between this forum and the Arduino ones.


Disclaimer: I don't have a Yun and know nothing about programming them.

Although this looks like a Unix problem. I think scripts have to export environment variables if you want to use them later.

Something like:


export FOO=bar

- Nick Gammon

www.gammon.com.au, www.mushclient.com
Top

Posted by Jantje   Belgium  (2 posts)  Bio
Date Reply #2 on Thu 14 May 2015 08:57 PM (UTC)
Message
Txs
spot on.

root@Marvin2:/www/cgi-bin/jantje# . ./SetGlobalSettings.sh
root@Marvin2:/www/cgi-bin/jantje# echo $DumpFile
/tmp/jantje/ttyATH0/dump.txt
root@Marvin2:/www/cgi-bin/jantje# export DumpFile=${DumpFile}
root@Marvin2:/www/cgi-bin/jantje# lua
Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio (double int32)
> print(os.getenv("DumpFile"))
/tmp/jantje/ttyATH0/dump.txt

I never really understood the concept of export. I think my understanding just increased :-))

Indeed yun is a linux (openwrt)

Jantje
Top

The dates and times for posts above are shown in Universal Co-ordinated Time (UTC).

To show them in your local time you can join the forum, and then set the 'time correction' field in your profile to the number of hours difference between your location and UTC time.


14,199 views.

It is now over 60 days since the last post. This thread is closed.     Refresh page

Go to topic:           Search the forum


[Go to top] top

Information and images on this site are licensed under the Creative Commons Attribution 3.0 Australia License unless stated otherwise.