在Perl中，如何在输入到达时立即处理输入，而不是等待换行？

I'd like to run a subcommand from Perl (or pipe it into a Perl script) and have the script process the command's output immediately, rather than waiting for a timeout, a newline, or a certain number of blocks. For example, let's say I want to surround each chunk of input with square brackets. When I run the script like this:I'd like to run a subcommand from Perl (or pipe