在Perl中讀取STDIN上的管道輸入之後，我可以提示用戶輸入嗎？

Question

我正在嘗試編寫一個讀取管道數據的perl腳本，然後根據這些數據提示用戶輸入。下面的腳本，prompt_for_action，就是我想要做的事：

#!/usr/bin/perl 

my @hosts =(); 
while (<>) { 
    my $host = $_; 
    $host =~ s/\n//; # strip newlines 
    push(@hosts, $host); 
} 

for my $host (@hosts) { 
    print "Do you want to do x with $host ? y/n: "; 
    chomp(my $answer = <>); 
    print "You said `$answer`.\n"; 
} 

，但是當我運行它沒有等待用戶輸入，它只是吹過，而無需等待我鍵入：

$ echo "test1.example.com 
> test2.example.com" | ./prompt_for_action 
Do you want to do x with test1.example.com ? y/n: You said ``. 
Do you want to do x with test2.example.com ? y/n: You said ``. 

如果我不讀從STDIN我的數據...

#!/usr/bin/perl 

my @hosts = ('test1.example.com', 'test12.example.com'); 

for my $host (@hosts) { 
    print "Do you want to do x with $host ? y/n: "; 
    chomp(my $answer = <>); 
    print "You said `$answer`.\n"; 
} 

然後腳本正常工作：

$ ./prompt_for_action 
Do you want to do x with test1.example.com ? y/n: y 
You said `y`. 
Do you want to do x with test12.example.com ? y/n: n 
You said `n`. 

是否連接到STDIN，然後提示用戶輸入可能？如果是這樣如何？

Answer 1

在Unix-y系統上，您可以打開/dev/tty僞文件進行讀取。

while (<STDIN>) { 
    print "from STDIN: $_"; 
} 
close STDIN; 

# oops, need to read something from the console now 
open TTY, '<', '/dev/tty'; 
print "Enter your age: "; 
chomp($age = <TTY>); 
close TTY; 
print "You look good for $age years old.\n"; 

Answer 2

一旦你通過STDIN管道，你的前STDIN（鍵盤輸入）正在被管道取代。所以我不認爲這是可能的。