Linux Perl：如何查找文件的存在并读取它（如果存在）

Linux Perl：如何查找文件的存在并读取它（如果存在） - > REALTIME(Linux Perl: How to look for the existence of a file and read it, if it exist -> REALTIME)

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（当然会显示一条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。

你们有什么想法我怎么能实现我的目标？

提前致谢。

There are similar questions like this, but what I am after is the real time detection of a file existence.

I have 2 linux box/PC.

[Linux Box 1] -> Generates a file named host (Manually executed)

[Linux Box 2] -> Has a daemon that sleeps every 2 seconds checks if the expected file exist. And if it exist it will execute my ssh command (ofc ourse a bunce of text will show up showing that it was executed bla bla bla).

PERL SCRIPT:

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

THE PROBLEM The problem is, it seems that I can't determine if the file exist real time even though it already exist.

BOX 1

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

BOX 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]

It would take almost like a minute or sometimes after 10 seconds to detect the existing file.

Its just weird.

You guys have any idea how could I achieve my goal?

Thanks in advance.