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Old 10-12-2008, 10:28 AM   #1
bcarson
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Child can't see parent's environment variable


I'm a Linux newbie, so I'm probably overlooking something obvious. I'm running Ubuntu 8.04 and trying to send updates to a SOLR server via a bash script.

Problem is, when I call the import script it gives me the error message:
You need to set the SOLR_HOME environmental variable before running this script.

Now, I can set SOLR_HOME using the export command, but the bash script still can't see it. The code in the bash script generating the error is this:
if [ -z "$SOLR_HOME" ]
then
echo "You need to set the SOLR_HOME ... "
fi

Strangely, the import script does run (without warnings) if I call it using a Perl script with the line:
`export SOLR_HOME=[directory];./import.sh`

So: Why would a child process not see an environment variable exported by its parent process? And why would commands issued from the command line fail while the same commands sent from a Perl script succeed?
 
Old 10-12-2008, 11:53 AM   #2
clvic
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How do you call the import script? Have you tried typing "echo $SOLR_HOME" in bash just after you set up its value?
 
Old 10-12-2008, 02:22 PM   #3
bcarson
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From the bash shell I type:

export SOLR_HOME=[directory]

After that, I can enter
echo $SOLR_HOME
and see the value I've just established; or I can enter env and see SOLR_HOME in the list. The script warns me to set the SOLR_HOME environment variable anyway.

I run the import script with the command:
sudo ./import.sh

the same command without "sudo" doesn't work: the shell just sits for a minute and then gives me another prompt. No warnings about permissions or anything. This is also puzzling behavior, but I'm not sure it's related.
 
Old 10-13-2008, 03:12 AM   #4
clvic
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So, that's the point: the "sudo" command does not preserve the environment, that is, it does not preserve variables values.
Give a look at the sudo manpage, the -E option and "SECURITY NOTES" describe how to deal with this. You can change your sudoers file to preserve the environment, or you can insert your environment modifications in a script, say do_all.sh, that called with 'sudo do_all.sh' changes the environment and eventually calls ./import.sh
 
Old 10-13-2008, 08:37 AM   #5
bcarson
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I suspected I was overlooking something obvious. Thanks!
 
Old 10-13-2008, 09:47 AM   #6
jschiwal
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You can run the script like this:
SOLR_HOME=[directory] ./import.sh

You can also use "env"
env SOLR_HOME=[directory] ./import.sh

If a variable is exported in a script, you need to source the script to retain the values.

Last edited by jschiwal; 10-13-2008 at 09:50 AM.
 
  


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