[31367] in Perl-Users-Digest
Perl-Users Digest, Issue: 2619 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Oct 2 11:09:44 2009
Date: Fri, 2 Oct 2009 08:09:09 -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, 2 Oct 2009 Volume: 11 Number: 2619
Today's topics:
Re: CGI and UTF-8 <hhr-m@web.de>
FAQ 5.42 How do I copy an entire directory? <brian@theperlreview.com>
open() close() same file many times <alfonso.baldaserra@gmail.com>
Re: open() close() same file many times <jurgenex@hotmail.com>
Re: open() close() same file many times <tzz@lifelogs.com>
Re: perl print ASCII <RedGrittyBrick@spamweary.invalid>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Re: simple hash <justin.0908@purestblue.com>
sort function warning, variable will not stay shared <cartercc@gmail.com>
Re: sort function warning, variable will not stay share <tadmc@seesig.invalid>
when pipe writer ignores SIGPIPE and other signals... <tzz@lifelogs.com>
Re: ~ substitute ' with ` <tadmc@seesig.invalid>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 2 Oct 2009 17:04:04 +0200
From: Helmut Richter <hhr-m@web.de>
Subject: Re: CGI and UTF-8
Message-Id: <Pine.LNX.4.64.0910021646280.4421@lxhri01.lrz.lrz-muenchen.de>
On Mon, 28 Sep 2009, sln@netherlands.com wrote:
> From the docs:
> " PRAGMAS
> -utf8
> This makes CGI.pm treat all parameters as UTF-8 strings.
> Use this with care, as it will interfere with the processing of binary uploads.
This is the same problem for *both* solutions offered in this thread:
the utf8 pragma, and setting binmode on both STDIN and STDOUT. In fact, I
have the suspicion that the effect of the pragma is not much more than
such
a setting.
> It is better to manually select which fields are expected to return utf-8 strings
> and convert them using code like this:
> use Encode;
> my $arg = decode utf8=>param('foo');
This is much less than half of the story. Getting a single parameter is a
fairly easy thing to do, with or without the CGI module. Using the CGI
module for producing HTML is only a very cumbersome way of writing
something in a complicated syntax that is much easier written directly in
HTML. For which task does the CGI module offer significant help, compared
with simply outputting HTML and analysing the input?
One of the (relatively few) things that are easier with the CGI module
than without is reusing the input values as defaults for the same form
when it must be output again because of incompletely or wrongly filled-in
values. Now, if I have to touch every single value, decode it, and store
it back into the structure, I could have hand-programmed that reuse with
not more effort.
--
Helmut Richter
------------------------------
Date: Fri, 02 Oct 2009 10:00:03 GMT
From: PerlFAQ Server <brian@theperlreview.com>
Subject: FAQ 5.42 How do I copy an entire directory?
Message-Id: <Dakxm.151739$nL7.31241@newsfe18.iad>
This is an excerpt from the latest version perlfaq5.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .
--------------------------------------------------------------------
5.42: How do I copy an entire directory?
(contributed by Shlomi Fish)
To do the equivalent of "cp -R" (i.e. copy an entire directory tree
recursively) in portable Perl, you'll either need to write something
yourself or find a good CPAN module such as File::Copy::Recursive.
--------------------------------------------------------------------
The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.
If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.
------------------------------
Date: Fri, 2 Oct 2009 04:41:49 -0700 (PDT)
From: alfonsobaldaserra <alfonso.baldaserra@gmail.com>
Subject: open() close() same file many times
Message-Id: <8ae73fb9-a0ef-440a-bc3d-01a2f488ade2@u36g2000prn.googlegroups.com>
hello list
i am writing a script to check memory usage on linux.
the script opens and closes /proc/meminfo 5 times in 5 seconds to
calculate memory usage on 5 seconds average, it goes something like
for (1..5) {
open MEM, "/proc/meminfo" or die "..."
while (<MEM>) {
...
}
close MEM;
sleep 1;
}
i was just wondering if this is advisable to open/close file that
fast? is there any better approach to do this?
looking for your valuable suggestions.
thank you.
------------------------------
Date: Fri, 02 Oct 2009 05:50:30 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: open() close() same file many times
Message-Id: <4ntbc5d2eicqtd8c787ec6tqsr0r1dkk61@4ax.com>
alfonsobaldaserra <alfonso.baldaserra@gmail.com> wrote:
>i am writing a script to check memory usage on linux.
>
>the script opens and closes /proc/meminfo 5 times in 5 seconds to
>calculate memory usage on 5 seconds average, it goes something like
>
>for (1..5) {
> open MEM, "/proc/meminfo" or die "..."
> while (<MEM>) {
> ...
> }
> close MEM;
> sleep 1;
>}
>
>i was just wondering if this is advisable to open/close file that
>fast? is there any better approach to do this?
Maybe all you need is a seek() call to reset the special file?
jue
------------------------------
Date: Fri, 02 Oct 2009 10:04:58 -0500
From: Ted Zlatanov <tzz@lifelogs.com>
Subject: Re: open() close() same file many times
Message-Id: <8763ax7s6d.fsf@lifelogs.com>
On Fri, 2 Oct 2009 04:41:49 -0700 (PDT) alfonsobaldaserra <alfonso.baldaserra@gmail.com> wrote:
a> the script opens and closes /proc/meminfo 5 times in 5 seconds to
a> calculate memory usage on 5 seconds average, it goes something like
a> for (1..5) {
a> open MEM, "/proc/meminfo" or die "..."
a> while (<MEM>) {
a> ...
a> }
a> close MEM;
a> sleep 1;
a> }
a> i was just wondering if this is advisable to open/close file that
a> fast? is there any better approach to do this?
That file is on a special procfs filesystem so the usual penalties don't
apply. Even on a regular filesystem this would not be a big deal, 1 Hz
is nothing in the context of modern CPUs and disks.
By the way, if you want *precise* readings, you don't want to use
sleep(1). You're sampling every 1sec + (time to open+close file), and
sleep() itself is not very precise so you may end up sampling irregular
intervals. Doing this correctly is not easy. At the very least, look
at the documentation for sleep() in `perldoc -f sleep'.
You can, however, run a pipe on vmstat: do
open VMSTAT, "vmstat 1|";
and read from it for as long as you need. You'll get updates every
second.
You could also look at Sys::Statistics::Linux, which I found via:
http://search.cpan.org/search?query=procfs&mode=all
it seems to provide much more than just memory info, so you may find it
useful.
Ted
------------------------------
Date: Fri, 02 Oct 2009 10:48:41 +0100
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: Re: perl print ASCII
Message-Id: <4ac5cc7b$0$2483$db0fefd9@news.zen.co.uk>
mud_saisem wrote:
> On Oct 2, 9:40 am, Jürgen Exner <jurge...@hotmail.com> wrote:
>> mud_saisem <mud_sai...@hotmail.com> wrote:
>>> Can anybody tell me how to print ASCII characters in perl ?
>> For printable ASCII characters you just print them like in
>>
>> print "This is an unsorted list of some ASCII characters";
>>
>>> eg: I would like to print the following ASCII character in perl using
>>> the following Alt 63214, which gives you ¯
>> That is not one of the 95 printable ASCII character (and neither one of
>> control characters), seehttp://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters
>>
>> jue
>
> Thanks for the response Jue, I understand that my use of the words
> "ASCII characters" was not entirely correct,
your use of "ASCII characters" was, unfortunately, entirely incorrect.
> but I was not sure how
> else to describe what I was after.
The character you want is a character in the Latin-1 (ISO 8859-1)
encoding. It's code point is 0xAF. It's name is Macron. I believe it is
intended to be used in composing certain long vowels in some languages
or in transliterations of some other languages.
>
> What I am after is a way to print ¯ character in perl and i am not
> sure how to do it.
You need to be clear about the encoding of the text file containing your
Perl program and the encoding in use by the display device. If both are
using ISO 8859-1 (or similar) you should be able to "print '¯';"
C:\>chcp 1252
Active code page: 1252
C:\>perl -e "print qq(XX\n¯\xAF)"
XX
¯¯
--
RGB
------------------------------
Date: Fri, 02 Oct 2009 02:24:21 -0500
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <pOSdnfzhdPY4N1jXnZ2dnUVZ_uidnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($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.noitatibaher\100cmdat/"
------------------------------
Date: Fri, 02 Oct 2009 09:52:28 -0000
From: Justin C <justin.0908@purestblue.com>
Subject: Re: simple hash
Message-Id: <3c65.4ac5cd5c.c2a5e@zem>
On 2009-10-02, Nene <rodbass63@gmail.com> wrote:
> Why is this code not working?
>
> #!/usr/bin/perl -w
> use strict;
> use warnings;
>
> my %years;
> while (<DATA>) {
> chomp;
> my $year = (split /\t/)[3];
> $years{$year}++;
> }
> foreach (sort keys %years) {
> print "In $_, $years{$_} CDs were released.\n";
> }
>
> __DATA__
> Bragg, Billy Workers' Playtime Cooking Vinyl 1987
> ###
>
> I keep getting:
>
> Use of uninitialized value in hash element at ./hash.pl line 9, <DATA>
> line 1.
There are no tabs (\t) in your data. If you edit the data and make sure
that they are *real* tabs then it works. You may want to choose an
alternative field separator.
Justin.
--
Justin C, by the sea.
------------------------------
Date: Fri, 2 Oct 2009 07:32:40 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: sort function warning, variable will not stay shared
Message-Id: <5c69bf99-f562-4915-8615-630eafbf8afd@37g2000yqm.googlegroups.com>
Suggestions for dealing with a warning for a sort function, please.
My query of a database table returns a reference to a hash of all the
records in the database. $content contains the hash reference for the
records. One of the columns is called 'name' which contains values
like 'George Washington', 'John Adams', and 'Thomas Jefferson'. I want
to iterate through the hash, sorting by the last name, e.g., Adams,
Jefferson, and Washington. The first name is immaterial.
The key is 'username' which is the primary key in the table and a
unique value.
This is the code I use to iterate through the hash:
foreach my $key (sort sortf keys %{$content})
{
#print values here, like
$content->{$key}{'name'}
$content->{$key}{'status'}
$content->{$key}{'username'}
$content->{$key}{'role'}
}
Here is the sortf function, which is an inner subroutine in the block
containing the hash iteration:
sub sortf
{
my ($alast, $blast);
($alast = $content->{$a}{'name'}) =~ s/.* (.*)$/$1/; #---line 164---
($blast = $content->{$b}{'name'}) =~ s/.* (.*)$/$1/;
return lc($alast) cmp lc($blast) if $alast ne $blast;
return $a cmp $b;
}
If I place this subroutine outside the block, it can't see $content
and generates a syntax error. If I place it in the block, it runs, but
generates a warning message. This has been running for some time, and
I'm inclined to ignore the warnings, but I would like to know that the
warnings are surplus.
Here is the warning message:
perl -cw CONSOLE.pm
[Fri Oct 2 10:26:09 2009] CONSOLE.pm: Variable "$content" will not
stay shared at CONSOLE.pm line 164.
CONSOLE.pm syntax OK
Suggestions?
TIA, CC.
------------------------------
Date: Fri, 02 Oct 2009 09:58:53 -0500
From: Tad J McClellan <tadmc@seesig.invalid>
Subject: Re: sort function warning, variable will not stay shared
Message-Id: <slrnhcc4eg.c4c.tadmc@tadmc30.sbcglobal.net>
ccc31807 <cartercc@gmail.com> wrote:
> One of the columns is called 'name' which contains values
> like 'George Washington', 'John Adams', and 'Thomas Jefferson'.
Does it contain names like
George Forman Jr
Susan Saint James
Kim Jong Il
??
> ($blast = $content->{$b}{'name'}) =~ s/.* (.*)$/$1/;
Then you will get
Jr
James
Il
instead of
Forman
Saint James
Kim
...
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.noitatibaher\100cmdat/"
------------------------------
Date: Fri, 02 Oct 2009 09:55:46 -0500
From: Ted Zlatanov <tzz@lifelogs.com>
Subject: when pipe writer ignores SIGPIPE and other signals...
Message-Id: <87ab097slp.fsf@lifelogs.com>
I ran into a program (call it XYZ) that ignores SIGPIPE and many other
signals, so doing:
...
open J, "$command|" or die "Could not open command [$command]: $!";
...
close J;
would hang my program forever (XYZ gets SIGPIPE but never exits, so my
program waits on the child PID forever). I solved it like this:
sub cleanup
{
# XYZ ignores SIGPIPE so we can't just close the pipe handle
# we have to kill every XYZ started in a subshell by us... annoying huh?
my @shells = `pgrep -P $$`;
foreach my $shell (@shells)
{
chomp $shell;
print "Killing XYZs with parent $shell\n";
system(pkill => -9 => -f => -P => $shell => 'XYZ');
}
close \*J;
}
Just a kill was not enough, it had to be -9.
Proc::ProcessTable was not available at the time, though I may use it
eventually.
I was wondering if my approach was flawed and I am missing something
obvious, or if there's a better way to achieve this.
Ted
------------------------------
Date: Fri, 02 Oct 2009 06:56:38 -0500
From: Tad J McClellan <tadmc@seesig.invalid>
Subject: Re: ~ substitute ' with `
Message-Id: <slrnhcbpoq.9nr.tadmc@tadmc30.sbcglobal.net>
[ Please do not top-post.
Text rearranged into a sensible order.
]
BJ <BJ@Isabe.com> wrote:
> "Tad J McClellan" <tadmc@seesig.invalid> wrote in message
> news:slrnhcb1ap.50r.tadmc@tadmc30.sbcglobal.net...
>> BJ <BJ@Isabe.com> wrote:
>>
>>> We are trying to get a text area from screen and edit it to
>>> replace ' with `
>>
>>
>> $title =~ tr/'/`/;
>>
>>
>> --
>> Tad McClellan
>> email: perl -le "print scalar reverse qq/moc.noitatibaher\100cmdat/"
It is bad manners to quote .sigs.
> Sorry, no good the same result.
Huh?
Did you try it?
I did.
-----------------------
#!/usr/bin/perl
use warnings;
use strict;
my $title = "substitute ' with `";
$title =~ tr/'/`/;
print "$title\n";
-----------------------
Works fine.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.noitatibaher\100cmdat/"
------------------------------
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>
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------------------------------
End of Perl-Users Digest V11 Issue 2619
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