为什么即使我已经重定向到 /dev/null，cron 仍然向我发送程序输出？

Question

我正在尝试通过 cron 重新启动系统进程，并通过电子邮件发送该进程的启动输出。我认为将 STDOUT 和 SDTERR 重定向到 /dev/null 会“静音”输出，但唉，这不起作用。如何让 cron 以静默方式重新启动此服务？crontab 条目：

0 6 * * * service sympa stop &>/dev/null; service sympa start &> /dev/null

重启电子邮件的示例输出：

 Stopping Sympa bounce manager bounced
   ...done.
 * Stopping Sympa task manager task_manager
   ...done.
 * Stopping Sympa mailing list archive manager archived
   ...done.
 * Stopping Sympa mailing list manager sympa
   ...done.
 ... waiting Prototype mismatch: sub Lock::LOCK_SH () vs none at /home/sympa/bin/Lock.pm line 38.
Constant subroutine LOCK_SH redefined at /home/sympa/bin/Lock.pm line 38.
Prototype mismatch: sub Lock::LOCK_EX () vs none at /home/sympa/bin/Lock.pm line 39.
Constant subroutine LOCK_EX redefined at /home/sympa/bin/Lock.pm line 39.
Prototype mismatch: sub Lock::LOCK_NB () vs none at /home/sympa/bin/Lock.pm line 40.
Constant subroutine LOCK_NB redefined at /home/sympa/bin/Lock.pm line 40.

Answer 1

我想你会想要下面这行

service sympa stop >/dev/null 2>&1.

第一个命令标准输出发送到/dev/null然后2>&1使stderr (standard error)要被发送到哪里stdout(standard output)会被/dev/null造成supressing输出。