shell脚本报错Exec format error

问题：
脚本报错如下

Nov 29 18:18:58 db53 systemd: Failed at step EXEC spawning /etc/rc.d/init.d/realserver: Exec format error
Nov 29 18:18:58 db53 systemd: realserver.service: control process exited, code=exited status=203
Nov 29 18:18:58 db53 systemd: Failed to start (null).
Nov 29 18:18:58 db53 systemd: Unit realserver.service entered failed state.
Nov 29 18:18:58 db53 systemd: realserver.service failed.

解决：
在开头加上

#!/bin/sh