Get a file from an instance using SSM

gistfile1.txt

# Assumptions: 
#  - SSM agent is installed on instance
#  - Netcat is installed on instance
#  - Port 1234 is accessible and no other process is listening

# Set instance id
export INSTANCE_ID="i-123123123"

# Shell 1: Start session
aws ssm start-session --target $INSTANCE_ID

# In shell 1: Start netcat listener
cat filename | nc -l -p 1234

# Shell 2: Start port forwarding
aws ssm start-session --document-name AWS-StartPortForwardingSession --parameters '{"portNumber":["1234"],"localPortNumber":["1234"]}' --target $INSTANCE_ID

# Shell 3: Start netcat client
nc -w 3 127.0.0.1 1234 > filename