[32143] in Perl-Users-Digest
Perl-Users Digest, Issue: 3408 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Jun 10 06:09:46 2011
Date: Fri, 10 Jun 2011 03:09:07 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Fri, 10 Jun 2011 Volume: 11 Number: 3408
Today's topics:
Re: [RegEx] Optional parameter <NoSpamPleaseButThisIsValid3@gmx.net>
Re: [RegEx] Optional parameter <rweikusat@mssgmbh.com>
Re: [RegEx] Optional parameter (Alan Curry)
Re: [RegEx] Optional parameter <rweikusat@mssgmbh.com>
Re: [RegEx] Optional parameter <kkeller-usenet@wombat.san-francisco.ca.us>
Re: [RegEx] Optional parameter <uri@StemSystems.com>
Re: [RegEx] Optional parameter (Alan Curry)
Re: command pipe not working <uri@StemSystems.com>
Re: command pipe not working <herbert.burnswell@gmail.com>
Re: command pipe not working <uri@StemSystems.com>
Re: command pipe not working <herbert.burnswell@gmail.com>
Re: command pipe not working <uri@StemSystems.com>
Re: command pipe not working <herbert.burnswell@gmail.com>
Re: command pipe not working <nospam.gravitalsun@hotmail.com.nospam>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
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----------------------------------------------------------------------
Date: Thu, 09 Jun 2011 21:21:48 +0200
From: Wolf Behrenhoff <NoSpamPleaseButThisIsValid3@gmx.net>
Subject: Re: [RegEx] Optional parameter
Message-Id: <4df11d4d$0$6624$9b4e6d93@newsspool2.arcor-online.net>
On 09.06.2011 14:27, Rainer Weikusat wrote:
> Scottie <scottie383@gmail.com> writes:
>> Hi!
>> I've problem with one of Regular Expression. Following code is not
>> working properly - Perl produce warning "Use of uninitialized value in
>> string eq at /tmp/test.pl line 7", where line 7 = print "|
>> $backup_compressed|$type_of_backup|\n";
>> -------------8<-------------
>> #!/usr/bin/perl
>> use warnings;
>> use strict;
>>
>> while (<DATA>) {
>> my ($backup_compressed, $type_of_backup ) = $_ =~ /
>> channel.*starting\s(?!piece)(.*)\s(.*)\sdatafile.*/;
>> if ( $backup_compressed eq '') {
>> $backup_compressed = "not_compressed";
>> }
>> print "|$backup_compressed|$type_of_backup|\n";
>> }
>
> A nice demonstration why 'use warnings' makes no sense.
say "I disagree" . "!" x 10
> I've
> also dumped the 'use strict' which just about as useless 'use
> warnings'. If you want to check your code use, perl -cw -Mstrict ...
> and fix whatever you consider to be an actual problem)
And how will perl -cw be able to warn if these warnings only occur
during runtime? The other thing is that -w and use warnings do slightly
different things... (see "What's wrong with -w and $^W" in perllexwarn)
If you don't want warnings about uninitialised values, just switch them
off in a local block around the part where you want default values ("no
warnings 'uninitialized'").
And there is a big agreement that use strict IS useful and should be
used. The advantages are really obvious. Especially if you just do a
small change and think you don't need to test. Typos are possible even
with syntax highlighting and super modern editors. And I don't believe
you that you are checking all your programs with -Mstrict before running
them. How much time do you loose just because of this?
So unless you script is a one-liner (or maybe < 5 lines), use strict and
warnings. Always.
------------------------------
Date: Thu, 09 Jun 2011 21:07:37 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: [RegEx] Optional parameter
Message-Id: <87r572lqeu.fsf@sapphire.mobileactivedefense.com>
Wolf Behrenhoff <NoSpamPleaseButThisIsValid3@gmx.net> writes:
> On 09.06.2011 14:27, Rainer Weikusat wrote:
>> Scottie <scottie383@gmail.com> writes:
>>> Hi!
>>> I've problem with one of Regular Expression. Following code is not
>>> working properly - Perl produce warning "Use of uninitialized value in
>>> string eq at /tmp/test.pl line 7", where line 7 = print "|
>>> $backup_compressed|$type_of_backup|\n";
>>> -------------8<-------------
>>> #!/usr/bin/perl
>>> use warnings;
>>> use strict;
>>>
>>> while (<DATA>) {
>>> my ($backup_compressed, $type_of_backup ) = $_ =~ /
>>> channel.*starting\s(?!piece)(.*)\s(.*)\sdatafile.*/;
>>> if ( $backup_compressed eq '') {
>>> $backup_compressed = "not_compressed";
>>> }
>>> print "|$backup_compressed|$type_of_backup|\n";
>>> }
>>
>> A nice demonstration why 'use warnings' makes no sense.
>
> say "I disagree" . "!" x 10
In this case, the cause of the warning is that an undefined value is
passed in place of a string. But an undefined value stringifies to an
empty string and there is no reason to warn about that (actually, the
standard Sys::Syslog module also triggers a lot of these warnings).
There is no point in printing this over and over again, everytime the
code is being used.
>> I've also dumped the 'use strict' which just about as useless 'use
>> warnings'. If you want to check your code use, perl -cw -Mstrict ...
>> and fix whatever you consider to be an actual problem)
>
> And how will perl -cw be able to warn if these warnings only occur
> during runtime?
Who is going to look at the warnings appearing during runtime, except
possibly a developer during testing? They are not useful for users.
> The other thing is that -w and use warnings do slightly
> different things... (see "What's wrong with -w and $^W" in
> perllexwarn)
The -w text essentially boils down to "don't expect CPAN modules to
compile without printing useless warnings if you enable warnings when
compiling them", IOW, these modules obviously don't start with 'use
warnings' ...
[...]
> And there is a big agreement that use strict IS useful and should be
> used.
I didn't claim that it wasn't useful. But again, it is only useful
during development. In production code, it just causes a miniscule
slowdown without any useful effect.
> The advantages are really obvious. Especially if you just do a
> small change and think you don't need to test.
If you do this kind of stuff, 'use strict' won't save you.
> Typos are possible even with syntax highlighting and super modern
> editors. And I don't believe you that you are checking all your
> programs with -Mstrict before running them. How much time do you
> loose just because of this?
Not as much time as I would loose by trying to test something which
won't work because of errors that can be detected at compile time,
anyway. Usually, I have Makefiles for anything non-trivial I write in
Perl and these Makefiles will do automatic checks of every file which
changed when typing make.
------------------------------
Date: Thu, 9 Jun 2011 20:27:33 +0000 (UTC)
From: pacman@kosh.dhis.org (Alan Curry)
Subject: Re: [RegEx] Optional parameter
Message-Id: <israbl$l6b$1@speranza.aioe.org>
In article <4df11d4d$0$6624$9b4e6d93@newsspool2.arcor-online.net>,
Wolf Behrenhoff <NoSpamPleaseButThisIsValid3@gmx.net> wrote:
>On 09.06.2011 14:27, Rainer Weikusat wrote:
>> Scottie <scottie383@gmail.com> writes:
>>> Hi!
>>> I've problem with one of Regular Expression. Following code is not
>>> working properly - Perl produce warning "Use of uninitialized value in
>>> string eq at /tmp/test.pl line 7", where line 7 = print "|
>>> $backup_compressed|$type_of_backup|\n";
>>> -------------8<-------------
>>> #!/usr/bin/perl
>>> use warnings;
>>> use strict;
>>>
>>> while (<DATA>) {
>>> my ($backup_compressed, $type_of_backup ) = $_ =~ /
>>> channel.*starting\s(?!piece)(.*)\s(.*)\sdatafile.*/;
>>> if ( $backup_compressed eq '') {
>>> $backup_compressed = "not_compressed";
>>> }
>>> print "|$backup_compressed|$type_of_backup|\n";
>>> }
>>
>> A nice demonstration why 'use warnings' makes no sense.
>
>say "I disagree" . "!" x 10
I can beat 10 '!'s worth of enthusiasm. I've been using
#!/usr/bin/perl -W
on every script since the -W flag was added. I like to known when there's a
screwy module and I don't think they should be allowed to hide their
screwiness.
In other news, gcc has grown a misfeature that provides the equivalent of
'no warnings' for C code, so now bad C writers will be able to hide their
screwiness from my aggressive -W flags there too. Dammit.
--
Alan Curry
------------------------------
Date: Thu, 09 Jun 2011 22:37:30 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: [RegEx] Optional parameter
Message-Id: <8739jin0th.fsf@sapphire.mobileactivedefense.com>
pacman@kosh.dhis.org (Alan Curry) writes:
[...]
> I've been using
> #!/usr/bin/perl -W
> on every script since the -W flag was added. I like to known when there's a
> screwy module and I don't think they should be allowed to hide their
> screwiness.
Out of my head, I know at least two cases where perl prints nonsense
warnings and use of 'no warning' is thus entirely legitimate:
- the already mentioned case of the 'uinitialized variable':
Technically, there is no such thing as an 'unitialized
variable' in Perl (meaning, something whose value is
essentially random, as would be the case in C). All
variables start out with a value of 'undef' and this will be
interpreted as 0 or '' if need be.
- a line of code supposed to print an error message after a
failed exec will usually trigger a warning. AFAIR, a
Perl-level workaround is available for these cases.
------------------------------
Date: Thu, 9 Jun 2011 15:03:12 -0700
From: Keith Keller <kkeller-usenet@wombat.san-francisco.ca.us>
Subject: Re: [RegEx] Optional parameter
Message-Id: <0is7c8xamn.ln2@goaway.wombat.san-francisco.ca.us>
On 2011-06-09, Rainer Weikusat <rweikusat@mssgmbh.com> wrote:
>
> Out of my head, I know at least two cases where perl prints nonsense
> warnings and use of 'no warning' is thus entirely legitimate:
>
> - the already mentioned case of the 'uinitialized variable':
> Technically, there is no such thing as an 'unitialized
> variable' in Perl (meaning, something whose value is
> essentially random, as would be the case in C). All
> variables start out with a value of 'undef' and this will be
> interpreted as 0 or '' if need be.
All "uninitialized" means in this context is that no value has actually
been assigned by the program. I consider it extremely useful in
situations where, for example, you have a data structure where you
expect values to be assigned but there isn't
foreach my $key (@expectedKeys) {
print $hash->{$key};
}
If a $hash->{$key} value hasn't been assigned to, I want to know that,
because it's likely a bug.
And, of course, using no warnings 'uninitialized' in areas where you
know that there will be uninitialized variables will suppress the
warning for you. Telling people not to use "use warnings;" because you
don't like the uninitialized warning is like driving a brad with a
piledriver.
--keith
--
kkeller-usenet@wombat.san-francisco.ca.us
(try just my userid to email me)
AOLSFAQ=http://www.therockgarden.ca/aolsfaq.txt
see X- headers for PGP signature information
------------------------------
Date: Thu, 09 Jun 2011 18:55:00 -0400
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: [RegEx] Optional parameter
Message-Id: <87wrgu7gzf.fsf@quad.sysarch.com>
>>>>> "RW" == Rainer Weikusat <rweikusat@mssgmbh.com> writes:
RW> pacman@kosh.dhis.org (Alan Curry) writes:
RW> [...]
>> I've been using
>> #!/usr/bin/perl -W
>> on every script since the -W flag was added. I like to known when there's a
>> screwy module and I don't think they should be allowed to hide their
>> screwiness.
RW> Out of my head, I know at least two cases where perl prints nonsense
RW> warnings and use of 'no warning' is thus entirely legitimate:
RW> - the already mentioned case of the 'uinitialized variable':
RW> Technically, there is no such thing as an 'unitialized
RW> variable' in Perl (meaning, something whose value is
RW> essentially random, as would be the case in C). All
RW> variables start out with a value of 'undef' and this will be
RW> interpreted as 0 or '' if need be.
if you coded that way regularly, i would never hire you or place you in
a perl job. there are special cases where that warning can be turned off
but to do in generally means you are not caring about your code and
data. you can argue until you are blue in the face but that is just
plain wrong. you should be aware of your data such that undef warnings
don't happen.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Thu, 9 Jun 2011 23:04:27 +0000 (UTC)
From: pacman@kosh.dhis.org (Alan Curry)
Subject: Re: [RegEx] Optional parameter
Message-Id: <isrjhr$ae7$1@speranza.aioe.org>
In article <8739jin0th.fsf@sapphire.mobileactivedefense.com>,
Rainer Weikusat <rweikusat@mssgmbh.com> wrote:
>pacman@kosh.dhis.org (Alan Curry) writes:
>
>[...]
>
>> I've been using
>> #!/usr/bin/perl -W
>> on every script since the -W flag was added. I like to known when there's a
>> screwy module and I don't think they should be allowed to hide their
>> screwiness.
>
>Out of my head, I know at least two cases where perl prints nonsense
>warnings and use of 'no warning' is thus entirely legitimate:
>
> - the already mentioned case of the 'uinitialized variable':
> Technically, there is no such thing as an 'unitialized
> variable' in Perl (meaning, something whose value is
> essentially random, as would be the case in C). All
> variables start out with a value of 'undef' and this will be
> interpreted as 0 or '' if need be.
I like explicit initializations, even if they aren't necessary. I write
things like
my $foo = undef;
to show that the initial undef value is intentionally used (tested with
defined() perhaps), and reserve the plain
my $foo;
for cases where the intent is that $foo should be assigned a new value before
any tests are done on it. Code is for people, not just the compiler.
As for the conversion to 0 or empty string, I can never predict which cases
are going to happen silently and which are going to trigger the warning. I've
been annoyed more often by that warning's failure to appear in situations
where it would have helped find a bug. This just isn't sane:
$ perl -Wle '$x=undef; $y="foo"; $x = $x . $y'
Use of uninitialized value $x in concatenation (.) or string at -e line 1.
$ perl -Wle '$x=undef; $y="foo"; $x .= $y'
$
--
Alan Curry
------------------------------
Date: Thu, 09 Jun 2011 14:44:38 -0400
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: command pipe not working
Message-Id: <87zklqc0a1.fsf@quad.sysarch.com>
>>>>> "HB" == Herb Burnswell <herbert.burnswell@gmail.com> writes:
HB> open(LOG, ">$logfile") || die "Couldn't open $logfile: $!";
HB> my $date = `date`;
HB> chomp($date);
don't do that as you are forking for no reason. use the POSIX strftime
function which can do the same thing. in fact it wraps the same library
that the date command uses.
HB> write_log(`last -R $line \\| head -1 2>&1`);
why are you escaping the | there? it is not a character that is special
inside a string. so that is passing \| to the shell which means a
literal | and it is not interpreted as a real pipe.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Thu, 9 Jun 2011 12:38:31 -0700 (PDT)
From: Herb Burnswell <herbert.burnswell@gmail.com>
Subject: Re: command pipe not working
Message-Id: <804d8aef-c7a3-4d16-b2f8-78b1ee21b001@s41g2000prb.googlegroups.com>
UG> don't do that as you are forking for no reason. use the POSIX
strftime
function which can do the same thing. in fact it wraps the same
library
that the date command uses.
Sounds good, I will make that change.
UG> why are you escaping the | there? it is not a character that is
special
inside a string. so that is passing \| to the shell which means a
literal | and it is not interpreted as a real pipe.
I thought it needed to be escaped but it's not working either way.
The head command is not being interpreted and I'm receiving the
following error in the $logfile:
sh[2]: |: not found.
Any ideas? Thank you for your suggestions..
Best,
Herb
------------------------------
Date: Thu, 09 Jun 2011 15:45:48 -0400
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: command pipe not working
Message-Id: <878vtaaivn.fsf@quad.sysarch.com>
>>>>> "HB" == Herb Burnswell <herbert.burnswell@gmail.com> writes:
UG> why are you escaping the | there? it is not a character that is
HB> special
HB> inside a string. so that is passing \| to the shell which means a
HB> literal | and it is not interpreted as a real pipe.
HB> I thought it needed to be escaped but it's not working either way.
HB> The head command is not being interpreted and I'm receiving the
HB> following error in the $logfile:
HB> sh[2]: |: not found.
you have to show your code again. we can't guess what you typed into the
editor. my esp says you still have an escape or something in there as sh
is thinking that | is a command, not a pipe symbol. that may mean the part
before it is a complete statement ending in ; or something.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Thu, 9 Jun 2011 12:54:24 -0700 (PDT)
From: Herb Burnswell <herbert.burnswell@gmail.com>
Subject: Re: command pipe not working
Message-Id: <6300b5fd-f05a-4ee3-8460-4ee4d7153e19@e17g2000prj.googlegroups.com>
On Jun 9, 12:45=A0pm, "Uri Guttman" <u...@StemSystems.com> wrote:
> >>>>> "HB" =3D=3D Herb Burnswell <herbert.burnsw...@gmail.com> writes:
>
> =A0 UG> why are you escaping the | there? it is not a character that is
> =A0 HB> special
> =A0 HB> =A0 =A0 inside a string. so that is passing \| to the shell which=
means a
> =A0 HB> =A0 =A0 literal | and it is not interpreted as a real pipe.
>
> =A0 HB> I thought it needed to be escaped but it's not working either way=
.
> =A0 HB> The head command is not being interpreted and I'm receiving the
> =A0 HB> following error in the $logfile:
>
> =A0 HB> sh[2]: |: =A0not found.
>
> you have to show your code again. we can't guess what you typed into the
> editor. my esp says you still have an escape or something in there as sh
> is thinking that | is a command, not a pipe symbol. that may mean the par=
t
> before it is a complete statement ending in ; or something.
>
> uri
>
> --
> Uri Guttman =A0------ =A0u...@stemsystems.com =A0-------- =A0http://www.s=
ysarch.com--
> ----- =A0Perl Code Review , Architecture, Development, Training, Support =
------
> --------- =A0Gourmet Hot Cocoa Mix =A0---- =A0http://bestfriendscocoa.com=
---------
My apologies, I'm just getting used to the group postings again.
<snip>
sub create_log
{
open(LOG, ">$logfile") || die "Couldn't open $logfile: $!";
write_log_header(" Begin Log File");
close LOG;
}
sub finish_log
{
write_log_header(" End Log File");
}
sub write_log
{
open(LOG, ">>$logfile") || die "Couldn't open $logfile: $!";
print LOG @_;
close LOG;
}
sub write_log_header
{
my $date =3D `date`;
chomp($date);
open(LOG, ">>$logfile") || die "Couldn't open $logfile: $!";
print LOG ("\n
\n=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D\n");
print LOG $date . " ";
print LOG @_;
print LOG ("
\n=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D\n");
close LOG;
}
create_log;
my $file =3D "/path/to/file";
my $line;
open (INFO, $file);
my @lines =3D <INFO>;
close (INFO);
foreach $line (@lines)
{
write_log(`echo $line 2>&1`);
write_log(`last -R $line | head -1 2>&1`);
}
finish_log;
<snip>
Thanks,
Herb
------------------------------
Date: Thu, 09 Jun 2011 16:09:42 -0400
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: command pipe not working
Message-Id: <87pqmm937d.fsf@quad.sysarch.com>
>>>>> "HB" == Herb Burnswell <herbert.burnswell@gmail.com> writes:
HB> My apologies, I'm just getting used to the group postings again.
another tip is to reduce your problem to the minimal amount of code to
show it. also show the exact errors you see.
since the shell is the one showing the error, these are the only lines
you needed to show.
HB> write_log(`echo $line 2>&1`);
HB> write_log(`last -R $line | head -1 2>&1`);
and since the shell is the problem, you could just try to run the
backtick code and print the results. that is another simplification.
finally one more trick. how do you know what is actually being passed to
the backticks? a good idea is to put that whole string into a variable
first and printing it before you call the backticks. then you can see
what the shell sees. you can also manually pass that to the shell to
further debug that and then fix the perl issue. my guess is that $line
has a newline in it. this would make the | the start of a new command
and | isn't a found command which is what the shell said.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Thu, 9 Jun 2011 13:21:19 -0700 (PDT)
From: Herb Burnswell <herbert.burnswell@gmail.com>
Subject: Re: command pipe not working
Message-Id: <38fa94ef-f85f-4811-8d45-6134eb516bb5@v11g2000prk.googlegroups.com>
On Jun 9, 1:09=A0pm, "Uri Guttman" <u...@StemSystems.com> wrote:
> >>>>> "HB" =3D=3D Herb Burnswell <herbert.burnsw...@gmail.com> writes:
>
> =A0 HB> My apologies, I'm just getting used to the group postings again.
>
> another tip is to reduce your problem to the minimal amount of code to
> show it. also show the exact errors you see.
>
> since the shell is the one showing the error, these are the only lines
> you needed to show.
>
> =A0 HB> =A0 =A0 =A0 =A0 write_log(`echo $line 2>&1`);
> =A0 HB> =A0 =A0 =A0 =A0 write_log(`last -R $line | head -1 2>&1`);
>
> and since the shell is the problem, you could just try to run the
> backtick code and print the results. that is another simplification.
>
> finally one more trick. how do you know what is actually being passed to
> the backticks? a good idea is to put that whole string into a variable
> first and printing it before you call the backticks. then you can see
> what the shell sees. you can also manually pass that to the shell to
> further debug that and then fix the perl issue. my guess is that $line
> has a newline in it. this would make the | the start of a new command
> and | isn't a found command which is what the shell said.
>
> uri
>
> --
> Uri Guttman =A0------ =A0u...@stemsystems.com =A0-------- =A0http://www.s=
ysarch.com--
> ----- =A0Perl Code Review , Architecture, Development, Training, Support =
------
> --------- =A0Gourmet Hot Cocoa Mix =A0---- =A0http://bestfriendscocoa.com=
---------
Thank you for the tips, I'll use them moving forward.
You were right, $line did have a newline in it and "chomp $line;"
fixed the issue. I really appreciate your help.
Best,
Herb
------------------------------
Date: Thu, 09 Jun 2011 23:40:38 +0300
From: George Mpouras <nospam.gravitalsun@hotmail.com.nospam>
Subject: Re: command pipe not working
Message-Id: <isrb46$13g6$1@news.ntua.gr>
#!/usr/bin/perl
# this make some sense...
use strict;
my $file = "/work/foo.txt";
my $logf = "/work/foo.log";
open INFO, '<', $file or die "oups $^E\n"; END{close INFO};
open LOGF, '>', $logf or die "oups $^E\n"; END{close LOGF};
write_log_header(" Begin Log File");
while (<INFO>) {
write_log($_);
write_log(`echo blah 2>&1`);
}
write_log_header(" End Log File");
sub write_log_header {
write_log("\n==================================\n");
write_log( scalar(localtime time)." $_[0]");
write_log("\n==================================\n");
}
sub write_log { print LOGF $_[0] }
------------------------------
Date: Fri, 10 Jun 2011 02:16:33 -0500
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <VdqdnRl61plMWWzQnZ2dnUVZ5jqdnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
This newsgroup, commonly called clpmisc, is a technical newsgroup
intended to be used for discussion of Perl related issues (except job
postings), whether it be comments or questions.
As you would expect, clpmisc discussions are usually very technical in
nature and there are conventions for conduct in technical newsgroups
going somewhat beyond those in non-technical newsgroups.
The article at:
http://www.catb.org/~esr/faqs/smart-questions.html
describes how to get answers from technical people in general.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://www.rehabitation.com/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Do not use these guidelines as a "license to flame" or other
meanness. It is possible that a poster is unaware of things
discussed here. Give them the benefit of the doubt, and just
help them learn how to post, rather than assume that they do
know and are being the "bad kind" of Lazy.
A note about technical terms used here:
In this document, we use words like "must" and "should" as
they're used in technical conversation (such as you will
encounter in this newsgroup). When we say that you *must* do
something, we mean that if you don't do that something, then
it's unlikely that you will benefit much from this group.
We're not bossing you around; we're making the point without
lots of words.
Do *NOT* send email to the maintainer of these guidelines. It will be
discarded unread. The guidelines belong to the newsgroup so all
discussion should appear in the newsgroup. I am just the secretary that
writes down the consensus of the group.
Before posting to comp.lang.perl.misc
Must
This section describes things that you *must* do before posting to
clpmisc, in order to maximize your chances of getting meaningful replies
to your inquiry and to avoid getting flamed for being lazy and trying to
have others do your work.
The perl distribution includes documentation that is copied to your hard
drive when you install perl. Also installed is a program for looking
things up in that (and other) documentation named 'perldoc'.
You should either find out where the docs got installed on your system,
or use perldoc to find them for you. Type "perldoc perldoc" to learn how
to use perldoc itself. Type "perldoc perl" to start reading Perl's
standard documentation.
Check the Perl Frequently Asked Questions (FAQ)
Checking the FAQ before posting is required in Big 8 newsgroups in
general, there is nothing clpmisc-specific about this requirement.
You are expected to do this in nearly all newsgroups.
You can use the "-q" switch with perldoc to do a word search of the
questions in the Perl FAQs.
Check the other standard Perl docs (*.pod)
The perl distribution comes with much more documentation than is
available for most other newsgroups, so in clpmisc you should also
see if you can find an answer in the other (non-FAQ) standard docs
before posting.
It is *not* required, or even expected, that you actually *read* all of
Perl's standard docs, only that you spend a few minutes searching them
before posting.
Try doing a word-search in the standard docs for some words/phrases
taken from your problem statement or from your very carefully worded
"Subject:" header.
Really Really Should
This section describes things that you *really should* do before posting
to clpmisc.
Lurk for a while before posting
This is very important and expected in all newsgroups. Lurking means
to monitor a newsgroup for a period to become familiar with local
customs. Each newsgroup has specific customs and rituals. Knowing
these before you participate will help avoid embarrassing social
situations. Consider yourself to be a foreigner at first!
Search a Usenet archive
There are tens of thousands of Perl programmers. It is very likely
that your question has already been asked (and answered). See if you
can find where it has already been answered.
One such searchable archive is:
http://groups.google.com/advanced_search
If You Like
This section describes things that you *can* do before posting to
clpmisc.
Check Other Resources
You may want to check in books or on web sites to see if you can
find the answer to your question.
But you need to consider the source of such information: there are a
lot of very poor Perl books and web sites, and several good ones
too, of course.
Posting to comp.lang.perl.misc
There can be 200 messages in clpmisc in a single day. Nobody is going to
read every article. They must decide somehow which articles they are
going to read, and which they will skip.
Your post is in competition with 199 other posts. You need to "win"
before a person who can help you will even read your question.
These sections describe how you can help keep your article from being
one of the "skipped" ones.
Is there a better place to ask your question?
Question should be about Perl, not about the application area
It can be difficult to separate out where your problem really is,
but you should make a conscious effort to post to the most
applicable newsgroup. That is, after all, where you are the most
likely to find the people who know how to answer your question.
Being able to "partition" a problem is an essential skill for
effectively troubleshooting programming problems. If you don't get
that right, you end up looking for answers in the wrong places.
It should be understood that you may not know that the root of your
problem is not Perl-related (the two most frequent ones are CGI and
Operating System related), so off-topic postings will happen from
time to time. Be gracious when someone helps you find a better place
to ask your question by pointing you to a more applicable newsgroup.
How to participate (post) in the clpmisc community
Carefully choose the contents of your Subject header
You have 40 precious characters of Subject to win out and be one of
the posts that gets read. Don't waste them. Take care while
composing them, they are the key that opens the door to getting an
answer.
Spend them indicating what aspect of Perl others will find if they
should decide to read your article.
Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.cpan.org/authors/id/D/DM/DMR/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"top-posting", "Jeopardy" (because the answer comes before the
question), or "TOFU" (Text Over, Fullquote Under).
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://web.presby.edu/~nnqadmin/nnq/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan and many others on the comp.lang.perl.misc newsgroup.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
The above message is a Usenet post.
I don't recall having given anyone permission to use it on a Web site.
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
Administrivia:
To submit articles to comp.lang.perl.announce, send your article to
clpa@perl.com.
Back issues are available via anonymous ftp from
ftp://cil-www.oce.orst.edu/pub/perl/old-digests.
#For other requests pertaining to the digest, send mail to
#perl-users-request@ruby.oce.orst.edu. Do not waste your time or mine
#sending perl questions to the -request address, I don't have time to
#answer them even if I did know the answer.
------------------------------
End of Perl-Users Digest V11 Issue 3408
***************************************
