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Old 12-03-2004, 07:54 PM   #1
Jicksta
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Registered: Sep 2004
Distribution: Mandrake, Debian
Posts: 11

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Using Bash Script for Exporting and Returning Environmental Variables


Hi,

I'm trying to write a Bash script that checks if a specific environmental variable exists, and if not, prompts the user as to what they want its value to be.

I'm using the environmental variable to store the path to a program the user is expected to have installed. If my script does not find it, it will write the path the user inputs to the environmental variable it will use each time it's executed.

Here's what I've come up with:
Code:
if [ -z $The_Path ]; then
  echo -n "The_Path not found, enter a value:  "
  read The_Path
  export The_Path
else
  echo $The_Path
fi
(the -z argument returns boolean true if the string has 0 characters)

For some reason, each time this script runs, the environmental variable is detected to be empty and (obviously) never writes the variable permanently.

Is there something I'm overlooking?
 
Old 12-03-2004, 08:39 PM   #2
SirSlappy
Member
 
Registered: Jun 2003
Location: Glendale AZ
Distribution: Slackware 10
Posts: 153

Rep: Reputation: 30
well..

if ($ThePath | grep /home/user/blah); then
echo $ThePath
else
echo -n "The Path Not Found, enter a value: "
read The_Path
export The_Path
fi
 
Old 12-04-2004, 11:26 AM   #3
dustu76
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Registered: Sep 2004
Distribution: OpenSuSe
Posts: 153

Rep: Reputation: 30
Code:
[/home/soumen/tmp] $ cat d
if [ -z $The_Path ]; then
  echo -n "The_Path not found, enter a value:  "
  read The_Path
  export The_Path
else
  echo $The_Path
fi
[/home/soumen/tmp] $ d
The_Path not found, enter a value:  haha
[/home/soumen/tmp] $ echo $d

[/home/soumen/tmp] $ The_Path=haha
[/home/soumen/tmp] $ d
The_Path not found, enter a value:  why
[/home/soumen/tmp] $ export The_Path=haha
[/home/soumen/tmp] $ d
haha
[/home/soumen/tmp] $
I think that should make it clear.

HTH.
 
Old 12-04-2004, 04:14 PM   #4
jlliagre
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Registered: Feb 2004
Location: Outside Paris
Distribution: Solaris10, Solaris 11, Mint, OL
Posts: 9,491

Rep: Reputation: 355Reputation: 355Reputation: 355Reputation: 355
You script is never going to change its parent shell environment, unless you run it with the 'dot' builtin, like this:
Code:
$ . d
 
  


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