Linux Perl:如何查找文件的存在并读取它(如果存在) - > REALTIME

Question

有类似的问题,但我所追求的是文件存在的实时检测.

我有2个linux盒子/ PC.

[Linux Box 1] - >生成一个名为host的文件(手动执行)

[Linux Box 2] - >有一个守护进程,每2秒休眠一次,检查预期的文件是否存在.如果它存在,它将执行我的ssh命令(当然会显示一个文本显示它被执行了bla bla bla).

PERL SCRIPT:

ctr:
if (-e $file) { system ("ssh $script $host.$display"); } 
sleep(2);
goto ctr;

问题 问题是,我似乎无法确定文件是否实时存在,即使它已经存在.

方框1

[machine01:/home/machine01]% /MACHINE/TOOLS/perl/app/host_gen
> executed at 08/21/2015 21:40:32

方框2

Sleeping for 2 seconds [08/21/2015 21:40:22]
Sleeping for 2 seconds [08/21/2015 21:40:24]
Sleeping for 2 seconds [08/21/2015 21:40:26]
Sleeping for 2 seconds [08/21/2015 21:40:28]
Sleeping for 2 seconds [08/21/2015 21:40:30]
Sleeping for 2 seconds [08/21/2015 21:40:32] **<-expected execution**
Sleeping for 2 seconds [08/21/2015 21:40:34]
Sleeping for 2 seconds [08/21/2015 21:40:36]
Sleeping for 2 seconds [08/21/2015 21:40:38]
Sleeping for 2 seconds [08/21/2015 21:40:40]
Sleeping for 2 seconds [08/21/2015 21:40:42]
Sleeping for 2 seconds [08/21/2015 21:40:44]
Sleeping for 2 seconds [08/21/2015 21:40:46]
Sleeping for 2 seconds [08/21/2015 21:40:48]
Sleeping for 2 seconds [08/21/2015 21:40:50]
Sleeping for 2 seconds [08/21/2015 21:40:52]
Sleeping for 2 seconds [08/21/2015 21:40:54]
Sleeping for 2 seconds [08/21/2015 21:40:56]
Sleeping for 2 seconds [08/21/2015 21:40:58]
Sleeping for 2 seconds [08/21/2015 21:41:00]
Sleeping for 2 seconds [08/21/2015 21:41:02]
Sleeping for 2 seconds [08/21/2015 21:41:04]
Sleeping for 2 seconds [08/21/2015 21:41:06]
Sleeping for 2 seconds [08/21/2015 21:41:08]
Sleeping for 2 seconds [08/21/2015 21:41:10]
Sleeping for 2 seconds [08/21/2015 21:41:12] <- It was executed here
TYPE_AND_DISPLAY [wkss machine01.ult.ultera.omps.com:0]
TYPE [wkss] DISPLAY [machine01.ult.ultera.omps.com:0]

检测现有文件几乎需要一分钟或有时10秒.

这很奇怪.

你们有任何想法我怎么能实现我的目标？

提前致谢.

Answer 1

之前的serverfault.com问题:如何判断文件是否在Perl的远程文件系统上？

引用该线程;

默认情况下,大多数NFS客户端缓存目录信息60秒.

该线程中提到的解决方案:

使用noac选项在客户端上挂载NFS共享以禁用属性缓存,或使用acdirmin = 0,acdirmax = 0来禁用目录缓存.