Quick script if you want to add (or remove) a drain from all of your Heroku apps (or those matching a specific prefix)

herokuDrainProcessing

#!/bin/bash

while getopts "arp:d:" opt; do
  case $opt in
    a)
      adding=true
      ;;
    r)
      adding=false
      ;;
    p)
      prefix=$OPTARG
      ;;
    d)
      drain=$OPTARG
      ;;
    \?)
      echo "Unknown option -$OPTARG"
      exit 1;
      ;;
    :)
      echo "Option -$OPTARG requires an argument"
      exit 1;
  esac
done

if [ -z $adding ] ; then
  echo "usage (-a or -r) -d 'drainurl'  [OPTIONAL: -p 'App_prefix']"
  exit 1
fi

if [ -z $drain ] ; then
  echo "You haven't defined a drain"
  exit 1
fi

if [ -z $prefix ] ; then
  read -r -p "Are you sure you have no app prefix? [y/N] " response
  case $response in
    [yY][eE][sS]|[yY])
      ;;
    *)
      echo 'Please try again'
      exit 1;
      ;;
  esac
fi

function processDrain {
  if [[ $adding == true ]] ; then
    addDrain $1
  else
    removeDrain $1
  fi
}

function addDrain {
  echo "heroku drains:add ${drain} -a ${1}";
}

function removeDrain {
  echo "heroku drains:remove ${drain} -a ${1}";
}

for app in `heroku apps | grep -v =`; do
  if [[ $app =~ "@" ]] ; then
    true
  elif [[ -z $prefix ]] ; then
    processDrain $app
  elif [[ $app =~ $prefix ]] ; then
    processDrain $app
  fi

done

Added output verbiage and made the commands "live" by default: https://gist.github.com/nicjohnson/6186293