Wait for Docker container to start and immediately follow its logs

waitforandfollow.sh

#!/bin/bash -e

# Example:
#
# 1. In a terminal window: ./waitforandfollow.sh hello-world
# 2. In another terminal window: docker run hello-world

if [ "$#" -ne 1 ] ; then
  echo "$0: exactly 1 argument expected."
  exit 3
fi

found=false
cid=""
while [ "$found" = false ]
do
  for id in $(docker ps --filter ancestor="$1" --format="{{.ID}}"); do
    if [ "$id" != "" ] ; then
      found=true
      cid="$id"
    fi
  done 
done

docker logs -f "$cid"