[23247] in Perl-Users-Digest
Perl-Users Digest, Issue: 5468 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Sep 9 06:05:50 2003
Date: Tue, 9 Sep 2003 03:05:07 -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 Tue, 9 Sep 2003 Volume: 10 Number: 5468
Today's topics:
Re: GNU make & make.pl are dead: long live Perl makepp <occitan@esperanto.org>
Re: How To activate command line history in debugger? <occitan@esperanto.org>
Re: multiple arrays from one text file with one column <krahnj@acm.org>
Re: multiple arrays from one text file with one column (Anno Siegel)
Re: multiple arrays from one text file with one column <dominix"at"despammed.com>
pass cmd line file glob to grep for readdir (qanda)
Re: pass cmd line file glob to grep for readdir (Sam Holden)
Re: pass cmd line file glob to grep for readdir <REMOVEsdnCAPS@comcast.net>
Re: Perl Arguements <kkeller-usenet@wombat.san-francisco.ca.us>
Re: perldoc can't display doc (Ronald Fischer)
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Re: Problem with simple contact script. <wsegrave@mindspring.com>
Re: Problem with simple contact script. <wsegrave@mindspring.com>
Re: Problem with simple contact script. <noreply@gunnar.cc>
Re: Problem with simple contact script. <noreply@gunnar.cc>
Re: qr// question <mpapec@yahoo.com>
Re: qr// question (Sam Holden)
Re: Threads troubles <troc@pobox.com>
yEnc decoding anonymous@coolgroups.com
Re: yEnc decoding <postmaster@castleamber.com>
Re: <bwalton@rochester.rr.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Tue, 9 Sep 2003 09:31:44 +0200
From: Daniel Pfeiffer <occitan@esperanto.org>
Subject: Re: GNU make & make.pl are dead: long live Perl makepp
Message-Id: <20030909093144.44aa99e8.occitan@esperanto.org>
Oops, for those who didn't follow the link to my page, there was no link to=
makepp. So here it is: http://makepp.sourceforge.net/ and this is the dow=
nload link http://sourceforge.net/project/showfiles.php?group_id=3D43679 in=
case you want to apply my patch directly.
Daniel Pfeiffer <occitan@esperanto.org> skribis:
> Hi,
>=20
> I have so far not seen the advantage of my 100% Perl syntax - at least no=
t until Emacs learns to syntax highlight the specific parts. Since my proj=
ect <http://dapfy.bei.t-online.de/make.pl/> was progressing very slowly, I =
took a new look at its closest competitor, makepp. It is so much superior =
to GNU make, that I am putting up with make's strange syntax.
>=20
> Despite being written in Perl, until now it offered little access to Perl=
. That has now changed with this patch <http://dapfy.bei.t-online.de/make.=
pl/perl.patch> and corresponding test <http://dapfy.bei.t-online.de/make.pl=
/perl.test> I contributed to version 1.20. With that make.pl is dead, and =
I will also contibute my builtin commands to makepp.
>=20
> coralament / best Gr=F6tens / liebe Gr=FC=DFe / best regards / elkorajn s=
alutojn
> Daniel Pfeiffer
>=20
> -- GPL 3: take the wind out of Palladium's sails! --
> ------
> -- My other stuff here too, make.pl, sawfish...: --
> ------
> -- http://dapfy.bei.t-online.de/ --
coralament / best Gr=F6tens / liebe Gr=FC=DFe / best regards / elkorajn sal=
utojn
Daniel Pfeiffer
-- GPL 3: take the wind out of Palladium's sails! --
------
-- My other stuff here too, make.pl, sawfish...: --
------
-- http://dapfy.bei.t-online.de/ --
------------------------------
Date: Tue, 9 Sep 2003 09:37:37 +0200
From: Daniel Pfeiffer <occitan@esperanto.org>
Subject: Re: How To activate command line history in debugger?
Message-Id: <20030909093737.6b08b0ac.occitan@esperanto.org>
Saluton, Moin,
Kurt Kronschnabl <k.kronschnabl_nospm_@ica-intercom-akademie.de> skribis:
> does anybody know how to enable the command line history in the debugger?
>=20
> Under Suse 8.2 is it already active. Not under Knoppix 3.1/3.2.
>=20
> I am a newbie in perl and don't understand the explanation in "man=20
> perldeb" to install Term::ReadKey and Term::Readline.
Versuch's stattdessen mit Emacs M-x shell (M- hei=DFt normalerweise Alt-Tas=
te). Das gibt Dir eine Art Terminal in einem Emacs Puffer. Wenn Du auf de=
r letzten Zeile nach dem Prompt Return, M-p oder M-n benutzt ist das, das w=
as Du brauchst. Du hast aber auch die ganze Interaktion im Puffer, und kan=
nst von dort Befehle nochmal abschicken oder das ganze sogar editieren :-)
coralament / best Gr=F6tens / liebe Gr=FC=DFe / best regards / elkorajn sal=
utojn
Daniel Pfeiffer
-- GPL 3: take the wind out of Palladium's sails! --
------
-- My other stuff here too, make.pl, sawfish...: --
------
-- http://dapfy.bei.t-online.de/ --
------------------------------
Date: Tue, 09 Sep 2003 04:10:02 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: multiple arrays from one text file with one column
Message-Id: <3F5D52A0.7E303E64@acm.org>
Faz wrote:
>
> I have a text file in a single column which has name address, phone
> age of each people as below
>
> Name
> Address
> phone
> age
> Name
> Address
> phone
> age
>
> I want to put all the names in the names array, all the address in
> address array all the phone in the phone array etc
Why four different arrays? A single array of arrays or array of hashes would make more sense.
A simple example (untested):
open IN, 'text_file' or die "Cannot open text_file: $!";
my ( @names, @addresses, @phones, @ages );
until ( eof IN ) {
chomp( my $temp = <IN> );
push @names, $temp;
chomp( $temp = <IN> );
push @addresses, $temp;
chomp( $temp = <IN> );
push @phones, $temp;
chomp( $temp = <IN> );
push @ages, $temp;
}
close IN;
for my $index ( 0 .. $#names ) {
print "Name: $name[$index]\n";
print "Address: $addresses[$index]\n";
print "Phone: $phones[$index]\n";
print "Age: $ages[$index]\n\n";
}
Or with an array of arrays:
open IN, 'text_file' or die "Cannot open text_file: $!";
my @data;
until ( eof IN ) {
push @data, [ grep chomp, map scalar <IN>, 1 .. 4 ];
}
close IN;
for my $record ( @data ) {
print "Name: $record->[0]\n";
print "Address: $record->[1]\n";
print "Phone: $record->[2]\n";
print "Age: $record->[3]\n\n";
}
Or with an array of hashes:
open IN, 'text_file' or die "Cannot open text_file: $!";
my @data;
my @fields = qw/Name Address Phone Age/;
until ( eof IN ) {
@{ $data[ @data ] }{ @fields } = grep chomp, map scalar <IN>, 1 .. 4;
}
close IN;
for my $record ( @data ) {
for my $field ( @fields ) {
print "$field: $record->{$field}\n";
}
print "\n";
}
John
--
use Perl;
program
fulfillment
------------------------------
Date: 9 Sep 2003 09:32:48 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: multiple arrays from one text file with one column
Message-Id: <bjk6o0$shj$1@mamenchi.zrz.TU-Berlin.DE>
Faz <lfazal@hotmail.com> wrote in comp.lang.perl.misc:
> Hello
>
> I have a text file in a single column which has name address, phone
> age of each people as below
>
> Name
> Address
> phone
> age
> Name
> Address
> phone
> age
>
> I want to put all the names in the names array, all the address in
> address array all the phone in the phone array etc
my ( @names, @address, @phone, @age);
push @{ ( \ ( @names, @address, @phone, @age) )[ $. % 4]}, $_ while <DATA>;
Anno
------------------------------
Date: Mon, 8 Sep 2003 23:48:00 -1000
From: "dominix" <dominix"at"despammed.com>
Subject: Re: multiple arrays from one text file with one column
Message-Id: <3f5da1c3$0$13306$626a54ce@news.free.fr>
"Faz" <lfazal@hotmail.com> wrote in message
news:13ddbd75.0309081829.1a6803cc@posting.google.com...
> Hello
>
> I have a text file in a single column which has name address, phone
> age of each people as below
>
> Name
> Address
> phone
> age
> Name
> Address
> phone
> age
>
> I want to put all the names in the names array, all the address in
> address array all the phone in the phone array etc
>
> Please help
>
> Thanks
OK, I know it's a perl forum, but in that case shouldn't it be faster to use
sed like
cat myfile |sed -e " /.*/{
N
N
N
s/\n/;/g
}"
which produce
Name;Address;phone;age
Name2;Address2;phone2;age2
...
HTH
--
dominix
------------------------------
Date: 8 Sep 2003 22:57:15 -0700
From: fumail@freeuk.com (qanda)
Subject: pass cmd line file glob to grep for readdir
Message-Id: <62b4710f.0309082157.4c16ee32@posting.google.com>
Hi all
I want to process lots of files (too many for the shell to expand on
one line) so I use readdir instead of glob. If I know the file glob
to use such as file*.ext I can put this directly into the grep ...
local @ARGV = grep /file.*\.ext/, readir CURDIR;
My question is how can I take a file glob on the command line and
transform it into an expression for grep. I suppose this also implies
we must prevent the shell from expanding by quoting the expression
such as myscript *file*.ext"
Thanks.
------------------------------
Date: 9 Sep 2003 06:29:54 GMT
From: sholden@flexal.cs.usyd.edu.au (Sam Holden)
Subject: Re: pass cmd line file glob to grep for readdir
Message-Id: <slrnblqsr2.bh4.sholden@flexal.cs.usyd.edu.au>
On 8 Sep 2003 22:57:15 -0700, qanda <fumail@freeuk.com> wrote:
>
> My question is how can I take a file glob on the command line and
> transform it into an expression for grep. I suppose this also implies
> we must prevent the shell from expanding by quoting the expression
> such as myscript *file*.ext"
Why not use perl's glob function (perldoc -f glob)?
--
Sam Holden
------------------------------
Date: Tue, 09 Sep 2003 04:54:07 -0500
From: "Eric J. Roode" <REMOVEsdnCAPS@comcast.net>
Subject: Re: pass cmd line file glob to grep for readdir
Message-Id: <Xns93F13C331B0Esdn.comcast@206.127.4.25>
fumail@freeuk.com (qanda) wrote in news:62b4710f.0309082157.4c16ee32
@posting.google.com:
> Hi all
>
> I want to process lots of files (too many for the shell to expand on
Have you considered using the xargs shell command?
--
Eric
$_ = reverse sort $ /. r , qw p ekca lre uJ reh
ts p , map $ _. $ " , qw e p h tona e and print
------------------------------
Date: Mon, 8 Sep 2003 21:25:44 -0700
From: Keith Keller <kkeller-usenet@wombat.san-francisco.ca.us>
Subject: Re: Perl Arguements
Message-Id: <8okjjb.9ti.ln@goaway.wombat.san-francisco.ca.us>
-----BEGIN xxx SIGNED MESSAGE-----
Hash: SHA1
On 2003-09-09, John Bokma <postmaster@castleamber.com> wrote:
>
> It has, but .pl is associated with perl so even without the she bang a
> .pl script is executed as perl.
>
> without an extension:
>
> (1)
>
> D:\Snippets>arg hello world
> 'arg' is not recognized as an internal or external command,
> operable program or batch file.
[snip]
Both you and Sam make good points--though I think Sam's
is slightly more valid, since neither your nor my error
messages look like the OPs. I don't have ksh available,
so I can't test whether that would produce the aberrant
behaviour the OP had.
> ^ please use the appropriate sig separator which is -- followed by one
> space. This means that most news readers automatically can remove the 12
> (not counting the sig sep) lines which includes the PGP signature. Thanks.
Well, I have made a conscious decision to not use the switch
to gpg that preserves the "-- " delimiter; according to the
man page it causes some problems with spaces. I apologize
for this nonstandard behaviour. Some newsreaders (like slrn)
can strip this nonstandard sig delimiter.
- --
kkeller-mmmspam@wombat.san-francisco.ca.us
(try just my userid to email me)
AOLSFAQ=http://wombat.san-francisco.ca.us/cgi-bin/fom
-----BEGIN xxx SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see http://www.gnupg.org
iEYEARECAAYFAj9dVkQACgkQhVcNCxZ5ID8ZMACcD4S40O4LuoyMXfaWa94bkwAd
OSgAn0HCVu2VRv1WeUZ//lhhMAQyesWa
=zpGZ
-----END PGP SIGNATURE-----
------------------------------
Date: 9 Sep 2003 00:26:12 -0700
From: ronaldf@eml.cc (Ronald Fischer)
Subject: Re: perldoc can't display doc
Message-Id: <219750c.0309082326.3c4bfc60@posting.google.com>
Bart Lateur <bart.lateur@pandora.be> wrote in message news:<4kgolv4bpk69tj0pvnnsn0c9vvirobve1t@4ax.com>...
> Ronald Fischer wrote:
>
> >I'm running Perl 5.8 under cygwin. When I do something like
> >
> >perldoc IO::File
> >
> >I get the error message
> >
> >Ignored /usr/lib/perl5/5.8.0/cygwin-multi-64int/IO/File.pm: unreadable
> >No documentation found for "IO::File".
> Check out the file permissions under that file tree. I'm assuming Cygwin
> does at least some attempt in emulating Unix in that regard.
$ ls -l /usr/lib/perl5/5.8.0/cygwin-multi-64int/IO/File.pm
-rwx------+ 1 Administ mkgroup_ 3955 Jun 2 15:41
/usr/lib/perl5/5.8.0/cygwin-multi-64int/IO/File.pm
so I tried:
$ chmod ugo+r /usr/lib/perl5/5.8.0/cygwin-multi-64int/IO/File.pm
$ perldoc IO::File
Error in tempfile() using /XXXXXXXXXX: Parent directory (/) is not
writable
at /usr/bin/perldoc line 564
Then I checked:
$ ls -ld /
drwx------+ 8 Administ mkgroup_ 4096 Jun 2 14:25 /
After doing a
$ chmod ugo+rwx /
I can indeed display the docs.
So you were right in that it had to do with file permissions. Setting
/ to 0777
is not as bad as it sounds, since this is Windows and the idea of Unix
groups
isn't present there anyway.... But I wonder why tempfile() wants to
create
his file in /. I thought that, by default, it would use the content of
the
environment variable TMP or TEMP (both are set on my system), or
otherwise
use /tmp. Any ideas about this?
Ronald
------------------------------
Date: Tue, 09 Sep 2003 02:23:31 -0500
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.4 $)
Message-Id: <qNacnWTIoopu4sCiU-KYvg@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.4 $)
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.
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://mail.augustmail.com/~tadmc/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
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_group_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
"Jeopardy" (because the answer comes before the question), or
"TOFU".
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 <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: Tue, 09 Sep 2003 04:12:17 GMT
From: "William Alexander Segraves" <wsegrave@mindspring.com>
Subject: Re: Problem with simple contact script.
Message-Id: <Bqc7b.774$c35.132@newsread1.news.atl.earthlink.net>
"Tom" <tom@ztml.com> wrote in message
news:59b4279a.0309081727.2ac8e787@posting.google.com...
> tadmc@augustmail.com (Tad McClellan) wrote in message
news:<slrnblpvn3.jjh.tadmc@magna.augustmail.com>...
> .
> .
> > > I hope this will meet your approval
> >
<snip>
>
> If this does not meet your approval, next stop... PERL 101 :(
Perl 101.
Tom, even though you've crafted a way to limit the addressees to a limited
set, you are still allowing user-supplied iput to pass unfiltered in other
fields.
Do a Google search for "cgiemail %0A bug" to see the exploit to which your
script is or may be vulnerable. With a simple test on my own system, I was
able to send E-mail to myself with name=%0ACC:my-email-address, proving your
script is vulnerable (at least when it is employed locally to send mail
though my ISP's SMTP server.
You may wish to examine Gunnar H's contact script for ways to prevent this
vulnerability.
Cheers.
Bill Segraves
P.S. Fortunately for you, your script appears to be broken at the "real"
site you revealed in your message. Lesson here: Don't use real sites for
your samples.
------------------------------
Date: Tue, 09 Sep 2003 05:51:52 GMT
From: "William Alexander Segraves" <wsegrave@mindspring.com>
Subject: Re: Problem with simple contact script.
Message-Id: <YTd7b.30$TC1.10@newsread2.news.atl.earthlink.net>
"Gunnar Hjalmarsson" <noreply@gunnar.cc> wrote in message
news:bjj0qq$j5lge$1@ID-184292.news.uni-berlin.de...
> Tad McClellan wrote:
<snip>
> > 2) It will function as a mail relay to any address in the whole
> > wide world!
>
> With hardcoded addresses? How?
Hi, Gunnar.
Remember the discussion we had on the "%0A exploit"? I'm not sure if this is
the problem to which Tad had referred; but Tom's script appears to allow
said exploit.
Cheers.
Bill Segraves
------------------------------
Date: Tue, 09 Sep 2003 08:46:59 +0200
From: Gunnar Hjalmarsson <noreply@gunnar.cc>
Subject: Re: Problem with simple contact script.
Message-Id: <bjjt6d$jihmo$1@ID-184292.news.uni-berlin.de>
William Alexander Segraves wrote:
> "Gunnar Hjalmarsson" <noreply@gunnar.cc> wrote in message
> news:bjj0qq$j5lge$1@ID-184292.news.uni-berlin.de...
>> Tad McClellan wrote:
>>> 2) It will function as a mail relay to any address in the whole
>>> wide world!
>>
>> With hardcoded addresses? How?
>
> Remember the discussion we had on the "%0A exploit"? I'm not sure
> if this is the problem to which Tad had referred; but Tom's script
> appears to allow said exploit.
Yes, you are probably right about that. Furthermore, Tom's first
script makes it also possible to submit any address directly in the
'towhom' field.
I just gave it a quick glance before asking the above question
yesterday, and only after John had pointed it out, my eyes were really
opened. ;-)
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
------------------------------
Date: Tue, 09 Sep 2003 08:52:02 +0200
From: Gunnar Hjalmarsson <noreply@gunnar.cc>
Subject: Re: Problem with simple contact script.
Message-Id: <bjjtft$jpq3k$1@ID-184292.news.uni-berlin.de>
William Alexander Segraves wrote:
> Tom, even though you've crafted a way to limit the addressees to a
> limited set, you are still allowing user-supplied iput to pass
> unfiltered in other fields.
>
> Do a Google search for "cgiemail %0A bug" to see the exploit to
> which your script is or may be vulnerable. With a simple test on my
> own system, I was able to send E-mail to myself with
> name=%0ACC:my-email-address, proving your script is vulnerable (at
> least when it is employed locally to send mail though my ISP's SMTP
> server.
>
> You may wish to examine Gunnar H's contact script for ways to
> prevent this vulnerability.
My ContactForm module is available at
http://search.cpan.org/author/GUNNAR/
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
------------------------------
Date: Tue, 09 Sep 2003 08:30:57 +0200
From: Matija Papec <mpapec@yahoo.com>
Subject: Re: qr// question
Message-Id: <h8sqlv8ucbjalkoiql4qn3jsbv2dkdo14s@4ax.com>
On Mon, 08 Sep 2003 21:19:19 GMT, "John W. Krahn" <krahnj@acm.org>
wrote:
>> my @arr = ('^match') x 2;
>
>In this instance the contents of $arr[0] and $arr[1] are exactly the
>same.
Yes, but after below line they /somehow/ aren't.
>> $_ = qr/$_/ for $arr[0];
>>
>> I wouldn't want to do $_ = qr/$_/ twice on same regex (I guess it's time
>> consuming?)
>
>What do you REALLY want to do?
I want hash/array of regexes but don't want to instantly compile them
all. I would like to compile them only when some particular is needed
and that "some particular" may be used more then once for matching,
while some regexes may not be used at all. If regex compiling is
significantly time consuming then this matters.
------------------------------
Date: 9 Sep 2003 06:47:40 GMT
From: sholden@flexal.cs.usyd.edu.au (Sam Holden)
Subject: Re: qr// question
Message-Id: <slrnblqtsc.bju.sholden@flexal.cs.usyd.edu.au>
On Tue, 09 Sep 2003 08:30:57 +0200, Matija Papec <mpapec@yahoo.com> wrote:
> On Mon, 08 Sep 2003 21:19:19 GMT, "John W. Krahn" <krahnj@acm.org>
> wrote:
>
>>> my @arr = ('^match') x 2;
>>
>>In this instance the contents of $arr[0] and $arr[1] are exactly the
>>same.
>
> Yes, but after below line they /somehow/ aren't.
>
>>> $_ = qr/$_/ for $arr[0];
>>>
>>> I wouldn't want to do $_ = qr/$_/ twice on same regex (I guess it's time
>>> consuming?)
>>
>>What do you REALLY want to do?
>
> I want hash/array of regexes but don't want to instantly compile them
> all. I would like to compile them only when some particular is needed
> and that "some particular" may be used more then once for matching,
> while some regexes may not be used at all. If regex compiling is
> significantly time consuming then this matters.
Something like:
use Memoize;
memoize('to_regex');
sub to_regex {
return qr/$_[0]/;
}
or
my %regexes;
sub to_regex {
$regexes{$_[0]} = qr/$_[0]/ unless exists $regexes{$_[0]};
return $regexes{$_[0]};
}
And then when you want to match use
$re = to_regex($string_of_regex);
to get the regex for that string.
Or with an array (or hash with tr/[]/{}/ ) of regexes you could do:
$arr[$index] = qr/$arr[$index]/ unless ref $arr[$index];
Before using $arr[$index] as a regex.
--
Sam Holden
------------------------------
Date: Tue, 09 Sep 2003 04:30:01 GMT
From: Rocco Caputo <troc@pobox.com>
Subject: Re: Threads troubles
Message-Id: <slrnblqlsp.et.troc@eyrie.homenet>
On Tue, 09 Sep 2003 03:19:46 GMT, Stefan Weiss wrote:
> Hi,
>
> I am trying to write a multiuser server (for games, chat, etc) in Perl.
> In time, this program might have to service >500 users simultaneously,
> who would be connected for some time. So I thought about using threads
> instead of forking a new process for every user, in order to keep my
> process table healthy and minimize inter-process communication overhead.
>
> I wrote simple server and client scripts to test the theory, but it
> does not work at all like I expected. The scripts are short enough,
> and I have cut away any unnecessary parts, so I included them both at
> the end of this posting.
>
> First problem - threads seem to be working fine, but when I look at the
> output of ps, there are still seperate processes for each connection.
> Shouldn't the threads all be contained in one large process? I'm using
> an ithreads-enabled current version of Perl with Linux 2.4.19.
Surprise! Linux's "threads" are lightweight processes that share memory
rather than copy-on-write it.
> Second problem - the process (group) just grows and grows with every
> connection, and no memory seems to be released after a client
> disconnects. I am aware that perl usually does not return freed memory
> to the system, but I was hoping that the memory would at least be
> reused for the next connection. This is what it looks like:
Which version of Perl are you using? I have it on good authority that
version 5.8.0 has a number of leaks that have since been fixed.
Then again, perhaps it's not good to join a thread from itself. I'm not
familiar enough with the intricacies of iThreads to say for sure.
> Third problem - I have absolutely no idea why, but when I run the
> client script in another terminal (or on another host even), and hit
> Ctrl-C while the client is still receiving data from the server, the
> server(!) will quit (and the client too, of course).
You should probably trace the source of the exit. The easiest way is to
throw in debugging warn or print statements to see what the server's
doing just before it stops.
> Can anybody explain to me what is happening? Is there a better approach
> than using threads? Should I just fork away for each new client?
Perl's threads use about half a megabyte apiece, and that's usually on
the low side of the estimate. 300 of them will require a minimum of
150MB of memory. That figure will rise quickly if you start building
objects and using modules.
You may want to consider a single-process, single-thread design, based
on four-argument select(), IO::Select, or a higher-level networking
library like POE.
>===[ file svr_thr_x.pl ]==================================================
>
> #!/usr/bin/perl
>
> use strict;
> use warnings;
>
> use threads qw(yield);
> use threads::shared;
>
> use Socket;
> use POSIX qw(strftime);
> use IO::Handle;
>
> use constant EOL => "\015\012";
>
> # configuration
> my $SVR_NAME = "XXXXXXX v0.001"; # name string
> my $SVR_ADDR = undef; # set to undef for INADDR_ANY
> my $SVR_PORT = 4887; # default port is 4887
> my $MAXCLIENTS = 100; # SOMAXCONN for system max
>
> # listen on SVR_ADDR:SVR_PORT
Consider IO::Socket::INET here.
> $SVR_ADDR = $SVR_ADDR ? inet_aton($SVR_ADDR) : INADDR_ANY;
> socket(SERVER, PF_INET, SOCK_STREAM, getprotobyname("tcp"))
> or die "Error opening socket: $!\n";
> setsockopt(SERVER, SOL_SOCKET, SO_REUSEADDR, pack("l", 1))
> or die "Error trying to set socket reusable option: $!\n";
> bind(SERVER, pack_sockaddr_in($SVR_PORT, $SVR_ADDR))
> or die "Error on bind: $!\n";
> listen(SERVER, $MAXCLIENTS)
> or die "Error on listen: $!\n";
>
> print "$SVR_NAME server running on port $SVR_PORT\n";
>
> # main loop
> my $curr_client_id = 0;
> for (;;) {
> my $cl_id = sprintf "CLIENT_%010d", $curr_client_id++;
> my $cl_sock = accept(my $client, SERVER);
> threads->create("serve_client", $client, $cl_id, $cl_sock);
> }
>
> # spawned threads use this sub
> sub serve_client {
> my ($client, $cl_id, $cl_sock) = @_;
> my ($cl_port, $cl_addr) = unpack_sockaddr_in($cl_sock);
> my $cl_name = gethostbyaddr($cl_addr, AF_INET);
> print "connection from $cl_name:$cl_port [", inet_ntoa($cl_addr), "]\n";
> autoflush $client 1;
> for (1 .. 10) {
You don't test whether print() succeeds here. How do you know when the
client has disconnected?
> print $client "... talking to $cl_name [id $cl_id] ...", EOL;
> sleep 1;
> }
> close $client;
Is it okay for a thread to join itself? This seems circular; would it
be the cause of memory not being released?
> threads->self->join;
> }
--
Rocco Caputo - rcaputo@pobox.com - http://poe.perl.org/
------------------------------
Date: 9 Sep 2003 04:03:22 -0400
From: anonymous@coolgroups.com
Subject: yEnc decoding
Message-Id: <3f5d894a_1@athenanews.com>
Hi.
I am trying to write some Perl scripts to decode the yEnc
files on Usenet. Not wanting to reinvent the wheel, I
tried this Convert::yEnc library that I came across.
Unfortunately, it requires Perl 5.8.0, and I only have
Perl 5.6.1. Does anyone know of any other simple ways to
get yEnc decoding up and running on Perl 5.6.1?
Thanks.
--------------------------------------------------------------------
For free web access to 50,000+ newsgroups, please visit
http://www.coolgroups.com/. Thanks
--------------------------------------------------------------------
------------------------------
Date: Tue, 09 Sep 2003 10:28:09 +0200
From: John Bokma <postmaster@castleamber.com>
Subject: Re: yEnc decoding
Message-Id: <1063096195.717055@halkan.kabelfoon.nl>
anonymous@coolgroups.com wrote:
> Hi.
>
> I am trying to write some Perl scripts to decode the yEnc
> files on Usenet. Not wanting to reinvent the wheel, I
> tried this Convert::yEnc library that I came across.
> Unfortunately, it requires Perl 5.8.0, and I only have
> Perl 5.6.1.
What prevents you from upgrading? (just curious)
--
Kind regards, feel free to mail: mail(at)johnbokma.com (or reply)
virtual home: http://johnbokma.com/ ICQ: 218175426
John web site hints: http://johnbokma.com/websitedesign/
------------------------------
Date: Sat, 19 Jul 2003 01:59:56 GMT
From: Bob Walton <bwalton@rochester.rr.com>
Subject: Re:
Message-Id: <3F18A600.3040306@rochester.rr.com>
Ron wrote:
> Tried this code get a server 500 error.
>
> Anyone know what's wrong with it?
>
> if $DayName eq "Select a Day" or $RouteName eq "Select A Route") {
(---^
> dienice("Please use the back button on your browser to fill out the Day
> & Route fields.");
> }
...
> Ron
...
--
Bob Walton
------------------------------
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:
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------------------------------
End of Perl-Users Digest V10 Issue 5468
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