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Old 12-28-2016, 02:36 AM   #1
P.G.Krish
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Question Confusion about shell script variable


Hi Guys,
I read the shell script which is used for deploying the aws, I found the below line. I dont understand why there is two variables (ZONE ,KUBE_AWS_ZONE). assigned for this.


Code:
ZONE=${KUBE_AWS_ZONE:-us-west-2a}

I checked with my local terminal

Code:
ZONE=${KUBE_AWS_ZONE:-us-west-2a}
Code:
echo $ZONE
It returns
Quote:
us-west-2a
Code:
echo $KUBE_AWS_ZONE
It returns nothing

I really dont, what is purpose of the KUBE_AWS_ZONE ?

Do you have any idea?kubernetes. I saw this command
 
Old 12-28-2016, 04:06 AM   #2
MadeInGermany
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ZONE is set to $KUBE_AWS_ZONE if non-null, otherwise to "us-west-2a".
 
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Old 12-28-2016, 04:13 AM   #3
pan64
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you can try to google: http://kubernetes.io/docs/getting-started-guides/aws/ or http://kubernetes.io/docs/admin/multiple-zones/, but if you have no idea what is that kube you need to know only: ZONE=${KUBE_AWS_ZONE:-us-west-2a} means use KUBE_AWS_ZONE if set, otherwise use us-west-2a
 
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Old 12-28-2016, 04:15 AM   #4
Turbocapitalist
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And the specific name to look for is parameter expansion. See the first item there on Wooledge's list.
 
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