> On Oct 22, 2022, at 11:46 PM, ToddAndMargo via perl6-users
> <perl6-users@perl.org> wrote:
>
> On 10/22/22 21:11, Bruce Gray wrote:
>>> On Oct 22, 2022, at 10:28 PM, ToddAndMargo via perl6-users
>>> <perl6-users@perl.org> wrote:
>>>
>>> Hi All,
>>>
>>> Is there a way to print only the last three lines
>>> in a long file (full on \n's).
>>>
>>>
>>> In Windows, I am trying to such the last the lines is
>>>
>>>> dir /s /A:-D /d /a
>>> ...
>>> Total Files Listed:
>>> 13671 File(s) 3,265,285,462 bytes
>>> 3917 Dir(s) 18,406,518,784 bytes free
>>>
>>> And yes, I know how to do it,
>> It would be generally helpful to tell us the way that you already "know how
>> to do it", so that if our guesswork is insufficiently astute, we don't waste
>> time telling you what you already know.
>>> but IT AIN'T PRETTY!
>>> I want pretty.
>>>
>>> -T
>> $ raku -e '.say for 1..1_000_000' > a.1
>> # Made a million-line file, for testing
>> $ time raku -e '.say for lines().tail(3)' a.1
>> 999998
>> 999999
>> 1000000
>> real 0m2.155s
>> user 0m1.727s
>> sys 0m0.249s
>> On Unix or Mac systems (and maybe Windows, UnxUtils or CygWin or GnuWin32 or
>> Microsoft's own "Windows Subsystem for Linux"), faster (and prettier) to
>> pipe to `tail -3`.
>> $ tail -3 a.1
>> (and I presume)
>> C:\> dir /s /A:-D /d /a | tail -3
>
> Thank you!
>
> No time of that type in Windows.
>
> This is my non-pretty way. It takes about two seconds.
>
>
> > dir . /s /A:-D /d /a | raku -e "my Str $x=slurp(); $x~~s/ .* 'File(s)
> > '//; $x~~s/ ' bytes' .*//; say $x"
>
> 3,275,857,307
You are welcome.
For that particular `dir` use, this is prettier, or at least shorter:
dir . /s /A:-D /d /a | raku -e "say lines[*-2].words[2]"
FYI, I just stumbled on a issue with your `s/ .* 'File(s) '//`code; because
you have two spaces after the `(s)`, the program give the wrong answer when the
total size of the files exceeds 10 GiB.
The directory tree I tried it on was that big, and so your code reported the
size of the subdirectory immediately before the grand total!
--
Hope this helps,
Bruce Gray (Util of PerlMonks)
