[RndTbl] (Simple?) Perl question

[Hartmut W Sager]

> ..... work the same? Is there any need to use backslashes here?

I always operate on the principle "if in doubt, escape it (i.e., backslash
it)".  Why spend time researching the bare minimum of escaping/backslashing
needed, when you can be safer as well as pre-empt future backslashing
requirements (if additional characters become special).  This also makes
the code more readable (yeah!).

I primarily apply this principle in regular expressions, but it is sensible
here too.

Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, +1-204-515-1700,
+1-810-471-4600


On 12 December 2016 at 13:57, Kevin McGregor <kevin.a.mcgregor at gmail.com>
wrote:

> Ugh. Even under Windows, doesn't
>
> $cmd =  "./psexec.exe //" . $server_name
>
> work the same? Is there any need to use backslashes here?
>
> On Mon, Dec 12, 2016 at 1:53 PM, Gilbert E. Detillieux <
> gedetil at cs.umanitoba.ca> wrote:
>
>> Yup, makes sense now...
>>
>> After this line...
>>
>> $cmd =  "./psexec.exe \\\\\\\\" . $server_name
>>
>> ... the cmd variable will contain "./psexec.exe \\\\server" (4
>> backslashes.  On running this line...
>>
>> my $output = `$cmd`
>>
>> ... the shell will see "./psexec.exe \\\\server", and the command will
>> see (after shell quote processing) argv[1] set to "\\server".
>>
>> Each level of "\" escape processing requires that you double the number
>> of "\" characters entered to get one through.  If you want to end up with
>> 2, after 2 levels, you need 8.
>>
>> Gilbert
>>
>> On 12/12/2016 1:43 PM, Kevin McGregor wrote:
>>
>>> I should add that this gets run immediately after via
>>>
>>> my $output = `$cmd`
>>>
>>> if that makes any difference.
>>>
>>> On Mon, Dec 12, 2016 at 1:40 PM, Kevin McGregor
>>> <kevin.a.mcgregor at gmail.com <mailto:kevin.a.mcgregor at gmail.com>> wrote:
>>>
>>>     I'm trying to decipher some Perl code which runs on a Windows
>>>     server, and I ran into this:
>>>
>>>     $cmd =  "./psexec.exe \\\\\\\\" . $server_name
>>>
>>>     I think the idea is to end up with
>>>
>>>     ./psexec.exe \\server
>>>
>>>     but WTF eight backslashes? Does that make any sense? If so, can
>>>     someone ELI5?
>>>
>>>     Kevin
>>>
>>
>> --
>> Gilbert E. Detillieux           E-mail: <gedetil at cs.umanitoba.ca>
>> Dept. of Computer Science       Web:    http://www.cs.umanitoba.ca/~ge
>> detil/
>> University of Manitoba          Phone:  (204)474-8161
>> Winnipeg MB CANADA  R3T 2N2     Fax:    (204)474-7609
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>
>
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