Perl不能正确打印 [英] Perl not printing properly

问题描述

好的，所以我有一些类似于下面看到的子例程，我的问题是打印功能不打印出来，直到实际的命令完成，我希望它打印

Has MySQL，安装：，然后执行该命令，然后打印确定。我已经尝试使用睡眠并尝试清除$ ssh_d对象。任何意见赞赏。不要担心在这个特定的子变量，这个问题正在发生。感谢你们。

  if（$ MySQL）
 {
 print有MySQL，正在安装：; 
 $ mysqlCmd =/path/to/script/mysql-install.pl $ person> / dev / null 2>& 1; 
 $ ssh_d-> cmd（$ mysqlCmd）; 
打印OK\\\
; 
 
  

解决方案

STDOUT通常是行缓冲，所以在打印换行符之前你不会看到你的输出。在打印之前，您可以设置 $ | 强制您的输出被打印。

要在每次打印后打开自动清理，请将 $ | 设置为1： / p>

  $ | = 1; 
 print输入3到5之间的数字：; 
 chomp（my $ answer =< STDIN>）; 
  

（请注意，$ |实际上并不是单个值，它会针对每个文件句柄分别进行跟踪。设置它时，会影响当前所选文件句柄的设置（请参阅 选择 ）。

Ok, so I have some sub routines similar to what you see below, my issue is that the print function is not printing out until the actual command is complete, I want it to print
"Has MySQL, Installing:", and then do the command then print OK. I have already tried using sleep and tried clearing the $ssh_d object. Any advice appreciated. Don't worry about the variables in this particular sub, the issue is happening all over. Thanks guys.

if ($MySQL)
{
    print "Has MySQL, Installing: ";
    $mysqlCmd = "/path/to/script/mysql-install.pl $person > /dev/null 2>&1";
    $ssh_d->cmd("$mysqlCmd");
    print "OK\n";
}

解决方案

STDOUT is usually line-buffered, so you won't see your output until you print a newline. You can set $| before printing to force your output to be printed.

To turn on autoflushing after each print, set $| to 1:

$| = 1;
print "Enter a number between 3 and 5: ";
chomp( my $answer = <STDIN> );

(Note that $| isn't actually a single value, it is tracked separately for each filehandle. When you set it, it affects the setting for the currently selected filehandle (see select).

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