G'day haukex,

Following your CB request, I ran this a few times for you. Firstly, here's what I'm using:

$ uname -a
Linux ibm-laptop.diversityarrays.com 4.1.34-33-default #1 SMP PREEMPT 
+Thu Oct 20 08:03:29 UTC 2016 (fe18aba) x86_64 x86_64 x86_64 GNU/Linux
$ perl -v | head -2 | tail -1
This is perl 5, version 18, subversion 2 (v5.18.2) built for x86_64-li
+nux-thread-multi
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"I've tried it lots of times, and no matter how long I wait to input something (or nothing) and hit enter, the output is invariably 2.

I got different results: ran it four different ways; only got 2 once.

I wrapped your one-liner in date commands to indicate the wait time; however, this didn't work when I issued an interrupt (^C). Here's the runs:

Hitting Enter almost immediately:

$ date; perl -wMstrict -le '$a=time;$SIG{ALRM}=sub{$b=time};alarm 2;<>
+;print $b-$a'; date
Sat Jul 21 05:55:19 AEST 2018

Use of uninitialized value $b in subtraction (-) at -e line 1, <> line
+ 1.
-1532116519
Sat Jul 21 05:55:20 AEST 2018
$
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Hitting Enter after several seconds:

$ date; perl -wMstrict -le '$a=time;$SIG{ALRM}=sub{$b=time};alarm 2;<>
+;print $b-$a'; date
Sat Jul 21 05:56:58 AEST 2018

2
Sat Jul 21 05:57:05 AEST 2018
$
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Hitting Ctrl-C almost immediately:

$ date; perl -wMstrict -le '$a=time;$SIG{ALRM}=sub{$b=time};alarm 2;<>
+;print $b-$a'; date
Sat Jul 21 05:59:28 AEST 2018
^C
$
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Hitting Ctrl-C after several seconds:

$ date; perl -wMstrict -le '$a=time;$SIG{ALRM}=sub{$b=time};alarm 2;<>
+;print $b-$a'; date
Sat Jul 21 06:00:13 AEST 2018
^C
$
[download]

Finally, please consider this response in isolation. I did start reading this thread when it first appeared; I stopped doing that when umber-hued material appeared to be headed for a cooling device. I followed the link you provided in the CB and replied directly; I didn't review any part of the thread before doing so.