无法使用打印写入文件 [英] can't write to file using print

问题描述

#!/usr/bin/perl

use strict;
use warnings;

open(my $vmstat, "/usr/bin/vmstat 1 2>&1 |");
open(my $foo, ">", "foo.txt") or die "can't open it for write";

while(<$vmstat>) {
   print "get ouput from vmstat and print it to foo.txt ...\n";
   print $foo $_;
}

当我运行上面的代码时，没有发生任何错误.但是在我按 ctr-c 退出后，foo.txt 中没有任何内容.你们中有人能告诉我为什么会这样吗?提前致谢.

when I run the above code, nothing wrong happend.but after I press ctr-c to quit, nothing in the foo.txt. could any of you tells me why does this happen? thanks in advance.

推荐答案

可能是输出被缓冲了而你不够耐心.试试这行额外的代码:

Maybe the output is being buffered and you are not being patient enough. Try this extra line of code:

open(my $foo, ">foo.txt") or die "can't open it for write";
select $foo; $| = 1; select STDOUT;

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