AWS CLI to get list of instance from

I assume you've already configured one AWS profile for each AWS account and those AWS profiles permit to assume a role having the ec2:DescribeInstances action (this is typically configured inside the ~/.aws/credentials and ~/.aws/config files).

The following script (list-instances.sh) could be written.

Default AWS region version

#!/bin/bash AWS_PROFILES=() AWS_PROFILES[0]=profile_for_account_1 AWS_PROFILES[1]=profile_for_account_2 AWS_PROFILES[2]=profile_for_account_3 for AWS_PROFILE in ${AWS_PROFILES[*]} do echo "== Profile '${AWS_PROFILE}' ==" aws ec2 describe-instances --profile "${AWS_PROFILE}" --filters Name=instance-state-code,Values=16 | jq -r '.Reservations[].Instances[].InstanceId' done 

Multi-regions version

#!/bin/bash AWS_PROFILES=() AWS_PROFILES[0]=profile_for_account_1 AWS_PROFILES[1]=profile_for_account_2 AWS_PROFILES[2]=profile_for_account_3 for AWS_PROFILE in ${AWS_PROFILES[*]} do for AWS_REGION in $(aws ec2 describe-regions | jq -r '.Regions[].RegionName') do echo "== profile: ${AWS_PROFILE}, region: ${AWS_REGION}" aws ec2 describe-instances --profile "${AWS_PROFILE}" --region "${AWS_REGION}" --filters Name=instance-state-code,Values=16 | jq -r '.Reservations[].Instances[].InstanceId' done done 

• You must have the jq command to parse the JSON output (see https://stedolan.github.io/jq/) ;
• If you want more than only the EC2 instance identifiers feel free to update the jq expression ;
• The --filters returns only EC2 instances in the running, be careful because it will not list instances in pending, shutting-down or stopping states (see the instance-state-code filter documentation here https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-instances.html) ;
• You can redirect the output to a file with ./list-instances.sh > instance-identifiers.txt. Then simply use cat instance-identifiers.txt | grep -v "==" | cat to loop again (here the cat command apply on each EC2 instance identifier, you can replace it by another command).

Hope this helps.

Baptiste