linux命令执行后无论成功与否都有一个返回值: 如果为 0,则表示命令执行成功,其它值则表示错误, 具体的错误码含义如下: OS error code 1: Operation not permitted OS error code 2: No such file or directory OS error code 3: No such process OS error code 4: Interrupted system call OS error code 5: Input/output error OS error code 6: No