Execute a command against one, or multiple SSM connected systems, return the output and exit

execute-ssm-command.sh

#!/bin/bash

run_command() {
    ident=$1
    cmd=$2
    >&2 echo "[+] Sending command to :: $i"; 
    params='{"command": ["'$cmd'"]}'
    # Read why unbuffer is needed here: https://github.com/aws/amazon-ssm-agent/issues/354
    unbuffer aws ssm start-session --document-name 'AWS-StartNonInteractiveCommand' --parameters  "$params" --target $ident
}

all() {
    command=${1:-hostname}
    platform=${2:-Linux}
    aws ssm get-inventory | jq '.Entities[] | .Data["AWS:InstanceInformation"] | select (. != null) | .Content[] | select(.InstanceStatus != "Terminated") | select(.PlatformType == "'$platform'") | "\(.PlatformType) \(.IpAddress) \(.ComputerName) \(.InstanceId)"' -r | sort -u | \
     while read i; do 
        ident=$(echo $i | awk '{print $4}'); 
        echo $i;
        run_command $ident "$command";
        sleep 1;
     done
}

if [ $1 = "all" ]; then
    all "$2" $3
else
    run_command $1 $2
fi

# Usage:
# ./execute-ssm-command.sh all 'hostname' [Linux | Windows]
#
# OR target a single system
#
# ./execute-ssm-command.sh i-123456789012 'command'