Cleanly run commands that require mysql running

mysqldo.sh

#!/bin/bash
# Executes the provided arguments as a shell command with a twist: if mysql is
# not already running: starts mysql, runs the commands, and stops mysql.
# Example usage:
# - mysqldo mysql -u root -p # will open an interactive shell and will stop mysql
#                            # when you leave the shell
# - mysqldo 'echo "show databases;" | mysql -u root -p"my_password"'
#   # note that if your commands involve pipes or anything that the shell
#   # interpretter would not pass to mysqldo as arguments, you should wrap the
#   # entire command in quotes.

already_running=
pid_file=/var/run/mysqld/mysqld.pid
stat=0

log() { echo -e "\033[0;33m[mysqldo] $1\033[00m" >&2; }
get_pid(){ [[ -e $pid_file ]] && cat $pid_file; }

main(){
  # start mysql if necessary
  if [[ -e $pid_file ]]; then
    log 'mysql already running'
    already_running=1
  else
    log 'starting mysql'
    mysqld_safe --skip-syslog >/dev/null 2>&1 &
    until [ -n "$(get_pid)" ]; do sleep 0.5; done
  fi
  log "$@"
  eval "$@"
  stat=$?
}

# stop mysql if it was not already running
clean(){
  [[ -n $already_running ]] && return
  log 'stopping mysql'
  get_pid | xargs kill
  until [[ -z $(get_pid) ]]; do sleep 0.5; done
}

trap clean SIGINT SIGKILL SIGTERM
main "$@"
clean
exit $stat