Below is the script that I am running
#!/bin/bash
region=('us-east-1' 'eu-central-1')
env=('prod' 'stage')
for region in "${region[@]}"
do
for env in "${env[@]}"
do
echo "$region"
echo "$env"
done
done
The output that I am getting is
us-east-1
prod
us-east-1
stage
eu-central-1
stage
eu-central-1
stage
But my expectation was to get
us-east-1
prod
us-east-1
stage
eu-central-1
prod
eu-central-1
stage
The script should run for both env conditions, but its running only once for prod and thrice for stage. Where am I going wrong here, any pointers or advice would be appreciated
You need to use a different variable for the loop than the initial array. Otherwise you are overwriting the array during the first iteration.
Here I'm using different variables for the array and the loop variable:
#!/bin/bash
regions=('us-east-1' 'eu-central-1')
envs=('prod' 'stage')
for region in "${regions[@]}"
do
for env in "${envs[@]}"
do
echo "$region"
echo "$env"
done
done
Output:
us-east-1
prod
us-east-1
stage
eu-central-1
prod
eu-central-1
stage
PS: Another option would be to use a string of multiple words and have bash iterating over that:
for a in foo bar
do
for b in baz qux
do
echo "${a}"
echo "${b}"
done
done
Arrays and scalar parameters lives in the same namespace, so the scalar will override the array in this example:
$ a=(hello world)
$ a=123
$ echo "${a[@]}"
123
In your example you are overriding the env variable in the inner loop, the execution is the following, in pseudo code:
expand "${region[@]}" into 'us-east-1' 'eu-central-1'
set region 'us-east-1'
expand "${env[@]}" into 'prod' 'stage'
set env 'prod'
... echo ...
set env 'stage'
... echo ...
set region 'us-central-1'
expand "${env[@]}" into 'stage'
...
Consider the following:
$ a="hello"; echo "${a[@]}"
hello