[31174] in Perl-Users-Digest
Perl-Users Digest, Issue: 2419 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri May 15 09:09:46 2009
Date: Fri, 15 May 2009 06:09:09 -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, 15 May 2009 Volume: 11 Number: 2419
Today's topics:
Re: comma operator <frank@example.invalid>
Re: comma operator <RedGrittyBrick@spamweary.invalid>
Re: comma operator <uri@PerlOnCall.com>
Define alarm in threads <scottalorda@libello.com>
Re: IO::Socket::INET on OSX or TCP stack problem <stuart@otenet.gr>
Re: IO::Socket::INET on OSX or TCP stack problem <stuart@otenet.gr>
Re: IO::Socket::INET on OSX or TCP stack problem <uri@PerlOnCall.com>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
problems with writing to an output file <ameya.r.sathe@gmail.com>
Re: problems with writing to an output file <smallpond@juno.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 15 May 2009 01:46:19 -0700
From: Franken Sense <frank@example.invalid>
Subject: Re: comma operator
Message-Id: <1vebr763b8r2h.wpqsywfdss3k$.dlg@40tude.net>
In Dread Ink, the Grave Hand of Tad J McClellan Did Inscribe:
> Franken Sense <frank@example.invalid> wrote:
>>
>> I'm reading up on perl today and find this in perldoc perlop:
>>
>> Comma Operator
>>
>> Binary "," is the comma operator. In scalar context it evaluates its
>> left argument, throws that value away, then evaluates its right
>> argument
>> and returns that value. This is just like C's comma operator.
>>
>> // end excerpt
>>
>> What is C's comma operator?
>
>
> It is an operator that evaluates its left argument, throws that value
> away, then evaluates its right argument and returns that value.
>
> It is just like Perl's comma operator.
This is a footnote from n1336.pdf:
100) A comma operator does not yield an lvalue.
Is this also true in perl?
--
Frank
I think if you're going to do a movie about Reagan you do it about the fact
that he created the huge deficit, that he armed the mujahadeen, that he
armed Saddam, that he armed Iran, he armed 2/3s of the Axis of Evil, he
funded terrorists in Central America, he was in my mind a terrible
president.
~~ Al Franken, Book TV, on CBS's Reagan movie
------------------------------
Date: Fri, 15 May 2009 10:31:30 +0100
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: Re: comma operator
Message-Id: <4a0d3672$0$26990$db0fefd9@news.zen.co.uk>
Franken Sense wrote:
> In Dread Ink, the Grave Hand of Tad J McClellan Did Inscribe:
>
>> Franken Sense <frank@example.invalid> wrote:
>>>
>>> I'm reading up on perl today and find this in perldoc perlop:
>>>
>>> Comma Operator
>>>
>>> Binary "," is the comma operator. In scalar context it evaluates its
>>> left argument, throws that value away, then evaluates its right
>>> argument
>>> and returns that value. This is just like C's comma operator.
>>>
>>> // end excerpt
>>>
>>> What is C's comma operator?
>>
>> It is an operator that evaluates its left argument, throws that value
>> away, then evaluates its right argument and returns that value.
>>
>> It is just like Perl's comma operator.
>
> This is a footnote from n1336.pdf:
>
> 100) A comma operator does not yield an lvalue.
>
> Is this also true in perl?
C> perl -e "$x,$y = 42; print qq(x=$x, y=$y)"
x=, y=42
--
RGB
------------------------------
Date: Fri, 15 May 2009 08:36:20 -0400
From: "Uri Guttman" <uri@PerlOnCall.com>
Subject: Re: comma operator
Message-Id: <87skj61r23.fsf@quad.sysarch.com>
>>>>> "R" == RedGrittyBrick <RedGrittyBrick@spamweary.invalid> writes:
R> Franken Sense wrote:
>>
>> 100) A comma operator does not yield an lvalue.
>>
>> Is this also true in perl?
C> perl -e "$x,$y = 42; print qq(x=$x, y=$y)"
R> x=, y=42
there is no lvalue in that first statement. comma binds lower than = so
that was $x followed by $y = 42 which works. the problem is finding a
way to have a comma operator which binds tighter than =. using parens
won't work since that makes a list and it isn't a comma op anymore but a
list element separator.
and finally WTF is franken sense asking dumb sidebar questions and
getting answers. he needs to focus on learning perl and not obscure side
issues like comma ops and lvalues (i bet he doesn't even know what the term
lvalue means)
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Free Perl Training --- http://perlhunter.com/college.html ---------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Fri, 15 May 2009 03:57:27 -0700 (PDT)
From: =?ISO-8859-1?Q?S=E9bastien_Cottalorda?= <scottalorda@libello.com>
Subject: Define alarm in threads
Message-Id: <b35b16af-c8bf-4114-9e31-e2f2cfba6cd4@r34g2000vbi.googlegroups.com>
I need to define an alarm like this.
eval {
my $thr = threads->new(\&run_cmd, params);
};
if ($@){
print "$@\n";
}
blah blah blah
sub run_cmd {
blah blah blah
threads->detach();
eval {
local $SIG{ALRM} = sub { die "TIMEOUT\n" };
alarm 10;
`$command_to_execute`;
alarm 0;
};
if ($@){
print "$@\n";
}
}
My problem is the following :
after waiting 10 seconds, either the master or the thread die.
How can I timeout the thread without affecting the master ?
Thanks in advance for any kind of help.
Sebastien
------------------------------
Date: Fri, 15 May 2009 11:43:00 +0300
From: Stuart Gall <stuart@otenet.gr>
Subject: Re: IO::Socket::INET on OSX or TCP stack problem
Message-Id: <guj9uk$vop$1@mouse.otenet.gr>
On 2009-05-10 19:29:47 +0300, Uri Guttman <uri@stemsystems.com> said:
>
> it sounds like maybe your osx stack is crapola. but that isn't a perl
> problem and i am sure many mac coders have written perl socket code for it.
That is what I am worried about. But if this problem was generic i.e.
any bad tcp packet results in the system getting hung in a retry loop
OSX would be very broken.
So it must be either a perl/osx thing or there must be something odd
about the TCP packets coming from these modbus devices which is
upsetting OSX.
>
> SG> Actually I am not realy sure that this is the correct syntax.
> SG> with perl -w I get
> SG> Argument "TCP_NODELAY" isn't numeric in setsockopt at
> SG> /System/Library/Perl/5.8.6/darwin-thread-multi-2level/IO/Socket.pm
> SG> line 247
>
> that is another problem. you didn't import the constant so it is being
> passed as just a string. but i doubt you really need this.
It imports as Socket::TCP_NODELAY
and you are right it made no diferance.
>
> >>
> SG> };
> >>
> SG> return ($SOCKETS{$IP});
> >>
> >> why do you return the socket from the global hash? you have it in $S (or
> >> in my version $sock).
> SG> Answered above $SOCKETS is local static.
>
> that doesn't answer why you return a hash lookup for the boolean
> return. return 1 is simpler, faster and more accurate.
<snip>
>
> SG> BEGIN {
>
> why the begin block? declaring empty vars subs in begin blocks does
> nothing.
It makes them static.
Is there another way to define a static variable ?
>
> SG> my %Sockets;
>
> SG> sub OpenSocket($) {
>
> why are you using prototypes? they are meant for one thing alone
> (changing how a sub call is parsed). they are not useful for arg
> checking or stuff.
I am using perl -w - I dont usually, but while I am trying to figure
out why this script does not work I am.
perl -w complains if you don't use prototypes. Or is there some other
way around that ?
>
------------------------------
Date: Fri, 15 May 2009 11:54:27 +0300
From: Stuart Gall <stuart@otenet.gr>
Subject: Re: IO::Socket::INET on OSX or TCP stack problem
Message-Id: <gujak3$vvi$1@mouse.otenet.gr>
On 2009-05-11 02:12:46 +0300, derykus@gmail.com said:
> On May 8, 2:05 pm, Stuart Gall <stu...@otenet.gr> wrote:
>> On 2009-05-07 23:03:16 +0300, dery...@gmail.com said:
>>
>> ...
>> print $socket $COMMAND;
>> $socket->read($r,6); #5th byte is the length byte
> *****
>> This is one place that it hangs with repeated retries
>
> Any possibility of a timeout as a workaround:
>
> eval { local $SIG{ALRM} = sub { die 'socket t/o';
> alarm(...);
> $socket->read($r, 6) };
> alarm(0);
> };
> if ( $@ =~ m{socket t/o} and not $socket->connected ) {
> ... reopen socket etc.
> }
I have sig alarm set anyway to catch the whole read/write loop.
OK Here is the realy odd thing
The first time a socket goes bad the read call will eventually return 0
bytes. and put the socket at eof.
I am using IO::Select to detect when a socket is READ_READY.
At the point that I call select no socket should be read ready so if it
is it means that it is at eof.
So this enables me to detect which socket has gone bad.
If I close and reopen that socket, the next socket that I attempt to do
IO hangs with the same issue, repeated TCP retries then RST. And one by
one they all fall down.
So my work around is that when I get a socket go eof I close all the
sockets and reopen them.
This then lets the code work for a few more loops.
Some how what ever is going wrong is corrupting all the sockets.
Incidentally I upgraded to 10.5.7 and amazingly I still have the same problem.
Stuart
------------------------------
Date: Fri, 15 May 2009 08:31:14 -0400
From: "Uri Guttman" <uri@PerlOnCall.com>
Subject: Re: IO::Socket::INET on OSX or TCP stack problem
Message-Id: <87ws8i1ral.fsf@quad.sysarch.com>
>>>>> "SG" == Stuart Gall <stuart@otenet.gr> writes:
SG> On 2009-05-10 19:29:47 +0300, Uri Guttman <uri@stemsystems.com> said:
SG> So it must be either a perl/osx thing or there must be something odd
SG> about the TCP packets coming from these modbus devices which is
SG> upsetting OSX.
hard to say from here. i highly doubt it is perl. if you want to verify
this do the same thing in c or another language. or google for this
situation and see if others have seen it.
>> why the begin block? declaring empty vars subs in begin blocks does
>> nothing.
SG> It makes them static.
SG> Is there another way to define a static variable ?
just declaring vars outside a sub makes them static. the issue is more
about scoping than compile vs run time which is what BEGIN controls.
SG> sub OpenSocket($) {
>>
>> why are you using prototypes? they are meant for one thing alone
>> (changing how a sub call is parsed). they are not useful for arg
>> checking or stuff.
SG> I am using perl -w - I dont usually, but while I am trying to figure
SG> out why this script does not work I am.
SG> perl -w complains if you don't use prototypes. Or is there some other
SG> way around that ?
huh?? perl doesn't complain if you don't use prototypes. it will complain if
you use wrong prototypes. don't put any () after the sub names. read
perldoc perlsub for more.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Free Perl Training --- http://perlhunter.com/college.html ---------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Fri, 15 May 2009 07:10:36 GMT
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <Mz8Pl.7126$Lr6.1813@flpi143.ffdc.sbc.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.noitatibaher\100cmdat/"
------------------------------
Date: Fri, 15 May 2009 05:47:07 -0700 (PDT)
From: Ameya <ameya.r.sathe@gmail.com>
Subject: problems with writing to an output file
Message-Id: <37996dda-9610-4323-a90d-30be25660f00@v4g2000vba.googlegroups.com>
Hello,
I have a directory with about 4000 CSV files (19MB each). I list the
files in another TXT file and then read each line and store it a $file
variable. I open $file which is a CSV file (19MB) and want to print a
variable in a file. However, that does not seem to be possible
although as a check I print the value on the screen successfully. As
an additional check I also try to print "hello" in the output file but
nothing gets printed. On the other hand if I print hello before
reading the CSV file then it does it successfully.
What could be the problem and how can I get my values to print in the
file. Following is the code snippet explaining the read and write
commands I use in my code.
********************************************
open my $fin, '<', $inFile or die "could not open file '$inFile' $!";
# Open the file for reading, $inFile is a CSV file
while (my $line = <$fh>) {
chomp($line);
...........
.........
$a = $line;
}
print $fout "$a\n" or die "Can't print in the file $outFile: $!"; #
There is no value of $a in $outFile
print $fout "Hello\n" or die "Can't print in the file $outFile: $!"; #
There is no "Hello" statement in $outFile
print "Hello\n" or die "Can't print in the file $outFile: $!"; #Prints
Hello on the screen
************************************************
Thanks and Regards,
Ameya
------------------------------
Date: Fri, 15 May 2009 06:05:00 -0700 (PDT)
From: smallpond <smallpond@juno.com>
Subject: Re: problems with writing to an output file
Message-Id: <1ef0ab45-61a6-4a16-8778-e01764c30d52@r36g2000vbr.googlegroups.com>
On May 15, 8:47 am, Ameya <ameya.r.sa...@gmail.com> wrote:
> Hello,
>
> I have a directory with about 4000 CSV files (19MB each). I list the
> files in another TXT file and then read each line and store it a $file
> variable. I open $file which is a CSV file (19MB) and want to print a
> variable in a file. However, that does not seem to be possible
> although as a check I print the value on the screen successfully. As
> an additional check I also try to print "hello" in the output file but
> nothing gets printed. On the other hand if I print hello before
> reading the CSV file then it does it successfully.
>
> What could be the problem and how can I get my values to print in the
> file. Following is the code snippet explaining the read and write
> commands I use in my code.
>
> ********************************************
> open my $fin, '<', $inFile or die "could not open file '$inFile' $!";
> # Open the file for reading, $inFile is a CSV file
> while (my $line = <$fh>) {
> chomp($line);
> ...........
> .........
> $a = $line;
>
> }
>
> print $fout "$a\n" or die "Can't print in the file $outFile: $!"; #
> There is no value of $a in $outFile
> print $fout "Hello\n" or die "Can't print in the file $outFile: $!"; #
> There is no "Hello" statement in $outFile
> print "Hello\n" or die "Can't print in the file $outFile: $!"; #Prints
> Hello on the screen
> ************************************************
>
> Thanks and Regards,
> Ameya
use warnings;
use strict;
Also, what is the size of $outfFile after this runs?
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
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End of Perl-Users Digest V11 Issue 2419
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