[SOLVED] Confusion about shell script variable

P.G.Krish · 12-28-2016, 02:36 AM

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

MadeInGermany · 12-28-2016, 04:06 AM

ZONE is set to $KUBE_AWS_ZONE if non-null, otherwise to "us-west-2a".

pan64 · 12-28-2016, 04:13 AM

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

Turbocapitalist · 12-28-2016, 04:15 AM

And the specific name to look for is parameter expansion. See the first item there on Wooledge's list.