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

Question

类似的问题也有，但我追求的是实时检测文件是否存在

我有2个linuxbox/PC.

[Linux 框 1] -> 生成一个名为 host 的文件（手动执行）

[Linux 框 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，我们会显示一堆文本，表明它已被执行 bla bla bla）。

PERL 脚本：

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。

BOX 1

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

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，有时需要 10 秒。

太奇怪了。

你们知道我怎样才能实现我的目标吗？

提前致谢。

Answer 1

Prior serverfault.com question: How can I tell if a file is on a remote filesystem with Perl?

引自该线程；

By default, most NFS clients cache directory information for 60 seconds.

该线程中提到的解决方案：

Mount the NFS share on the client with the noac option to disable attribute caching, or use acdirmin=0,acdirmax=0 to just disable directory caching.

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

Linux Perl: How to look for the existence of a file and read it, if it exist -> REALTIME

linux

perl

sleep

daemon