Example unicorn init.d script

#!/bin/sh
set -u
set -e

APP_ROOT=/var/railsapps/ryokan/current
PID=$APP_ROOT/tmp/pids/unicorn.pid
ENV=production
CMD="/opt/ruby-enterprise/bin/unicorn_rails -D -E $ENV -c config/unicorn.rb"

old_pid="$PID.oldbin"

cd $APP_ROOT || exit 1

sig () {
  test -s "$PID" && kill -$1 `cat $PID`
}

oldsig () {
  test -s $old_pid && kill -$1 `cat $old_pid`
}

case $1 in
start)
  sig 0 && echo >&2 "Already running" && exit 0
  $CMD
  ;;
stop)
  sig QUIT && exit 0
  echo >&2 "Not running"
  ;;
force-stop)
  sig TERM && exit 0
  echo >&2 "Not running"
  ;;
restart|reload)
  sig USR2 && echo reloaded OK && exit 0
  echo >&2 "Couldn't reload, starting '$CMD' instead"
  $CMD
  ;;
upgrade)
  sig USR2 && exit 0
  echo >&2 "Couldn't upgrade, starting '$CMD' instead"
  $CMD
  ;;
rotate)
  sig USR1 && echo rotated logs OK && exit 0
  echo >&2 "Couldn't rotate logs" && exit 1
  ;;
*)
  echo >&2 "Usage: $0 <start|stop|restart|upgrade|rotate|force-stop>"
  exit 1
  ;;
esac