Punishing Your Server With Perl

[eric-perl]

Hello, All:

A couple of years ago there was a great article by the title of "Punishing 
Your Server With Perl". (I believe that either Randal Schwartz or Ruben 
Lerner wrote the article.) Anyhow, I can't find it. I've checked Google 
but found nothing.

Where oh where did it go?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Punishing Your Server With Perl

[eric-perl]

On Thu, 13 Mar 2003 [EMAIL PROTECTED] wrote:
> A couple of years ago there was a great article by the title of "Punishing 
> Your Server With Perl". (I believe that either Randal Schwartz or Ruben 
> Lerner wrote the article.) Anyhow, I can't find it. I've checked Google 
> but found nothing.
> 
> Where oh where did it go?

Foiled again by having only half the facts:
1. The article's title is "Torture-testing Web Servers"
2. The article's author is Linconln Stein.

The article can be found at:

  http://stein.cshl.org/~lstein/torture/torture.html

There's also an article by Randal Schwartz that speaks to a related topic:

  http://www.stonehenge.com/merlyn/WebTechniques/col63.html

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Checking for .jpg/.gif/.png files

[eric-perl]

Hello, All:

I need to check files to make sure that they are .gif, .jpg, or .png
graphic files before processing them. How can I verify that?
  
e.g., In unix, the 'type' command returns the file's type.

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: shell command

[eric-perl]

On Tue, 3 Sep 2002, David T-G wrote:
> % all im trying to do is run the shell command: 
> % 
> % convert -quality 40 image.jpg resampled_image.jpg
> 
> Better yet, you should grab the PerlMagick module and just run the
> commands from within your perl script and forget the system call (or
> backticks or, IIRC, qx quoting).

Word to the wise: PerlMagick is _not_ the easiest thing in the world to 
use (especially if you have to install PerlMagick yourself instead of 
from .rpm). You can spend _a_lot_ of time installing/learning PerlMagick! 
If `convert` works for you, you might want to stay with that.

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Regex: Matching URL's

[eric-perl]

Hello, All:

I'm curious about the behavior of backreferences in a regular expression 
that I've created:

$url = m|^(http://)?((\.?[a-z0-9][a-z0-9\-]+)+(\.[a-z0-9]){2,3})/|

What's unusual about this regex is that the backreferences for any
sub-domains (i.e., www, ftp, &c.) are not caputured. e.g., Setting
$url equal to http://www.pretorious.net returns...

$1 = http://
$2 = www.pretorious.net
$3 = .pretorious
$4 = .net

While $2 holds the value that I am searching for, I'm still curious: How
can I flexibly capture any sub-domain portions of the hostnames. (Even the
tricky ones like www.developers.earthweb.com...)

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Regular Expressions: Grouping and backreferences...

[eric-perl]

Hello, All:

How can I capture all the words that contain 'at' in the string 'A fat cat
sat on my hat.'?

Any pointers?

$sentence = 'A fat cat sat on my hat.'
$sentence =~ m/(\wat)/;

returns:

$1 = 'fat'

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: converting a list into array

[eric-perl]

On Wed, 4 Sep 2002, Bob Showalter wrote:
>chomp(@list = );
>print join(',', map "'$_'", @list), "\n";
>__DATA__
>AAPL
>AMCO
>IBM
>ORCL

What is the __DATA__? Please explain.

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Removing a directory

[eric-perl]

Hello, All:

What's the simplest method to remove a directory *and* it's contents? 
(rmdir only works on empty directories.)

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Removing a directory

[eric-perl]

On Tue, 24 Sep 2002, Michael Fowler wrote:

> On Tue, Sep 24, 2002 at 10:38:59AM +0800, [EMAIL PROTECTED] wrote:
> > What's the simplest method to remove a directory *and* it's contents? 
> > (rmdir only works on empty directories.)
> 
> I'm somewhat surprised by the advice given so far (rm -rf and File::Remove;
> the first isn't portable, the second requires going to CPAN).  The simplest
> solution is to use rmtree from File::Path, which comes with Perl.  See
> perldoc File::Path.

Oh that's good - Thanks!

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Looping through readdir()

[eric-perl]

Hello, All:

When using...

while ($x = readdir(DH)) {
# What came before $x?
# What will come after $x?
}

How can I look at the next item in the directory?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Comparison: finding if a value is gt some value AND lt another

[eric-perl]

Hello, All:

Is there a simple way to find if a variable's value is within a range? 
e.g.,

  if (1 < $x < 5) { print 'foo'; }

or do I have to join two separate comparisons using the logical AND 
operator? e.g.,

  if (1 < $x and $x < 5) { print 'foo'; }

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

foreach() and while()

[eric-perl]

Hello, All:

When using foreach or while() on an array, how can I access the index of
the list that foreach()/while() is working upon? Is there an internal 
variable that stores this info like PHP's current()?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Condition Evaluation

[eric-perl]

Hello, All:

I'm testing to determine that a list of variables has been set and 
am baffled by how this conditional is evaluating:

CODE SNIPPET:
GetOptions(
'comment=s' => \$comment,   # Req'd arg
'directory=s'   => \$directory, # Req'd arg
'rows=i'=> \$max_rows,  # Req'd arg
'cols=i'=> \$max_cols,  # Req'd arg
'saturation:i'  => \$saturation # Optional arg
);

unless (defined $directory && defined $comment && defined $max_rows && 
  defined $max_cols && (!defined $saturation || abs($saturation) < 100)) {
# Print error messages
  }

WHAT'S HAPPENING:
Without setting $saturation...
 A. Everything works just fine if all of the *required* variables are set.
 B. Perl complains 'Use of uninitialized value in abs' if any of the 
*required* variables are not set.

WHAT I EXPECT TO HAPPEN:
Without setting $saturation...
  I thought that evaluation of the conditional would stop at the first 
   occurence of an undefined variable and that (!$defined $saturation ||
   abs($saturation) < 100) would _not_ be evaluated i.e., The abs() 
   portion of the test would not be performed.

HOW CAN I:
  1. Check that each of the required variables has been set *and*then*
  2. Check the value of $saturation _only_if_it_has_been_set_?

-- 
Eric Pretorious
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Condition Evaluation

[eric-perl]

On Mon, 30 Sep 2002, Michael Fowler wrote:
> I cannot duplicate your problem.  Given the code:
> 
> perl -wle 'print "hi" if defined $bar && (!defined $foo || abs($foo)
>< 100)'
> 
> I see no 'Use of uninitialized value' warnings, and no print.  Are you
> certain the code you posted is what you're actually using?  Is there
> relevant code prior to what you posted, such as initializations of your
> variables?

The snippet that I included in the message was a reduced version of the
script. I've attached the script to this message. (I hope that this isn't
a breach of etiquete.) Here's the first 20 lines or so...

#!/usr/bin/perl -w

use Text::Template;
use Image::Magick;
use Getopt::Long;
use File::Path;
use FindBin qw($Bin);
use POSIX;

use strict;
use vars qw($comment $directory $max_rows $max_cols $lg_dim $saturation
$normal $last_index $indiv_template $index_template @files @html_files
@old_indexes);

GetOptions(
'comment=s' => \$comment,
'directory=s'   => \$directory,
'rows=i'=> \$max_rows,
'cols=i'=> \$max_cols,
'largedim=i'=> \$lg_dim,
'normalize' => \$normal,
'saturation:i'  => \$saturation
);

unless (defined $directory && defined $comment && defined $max_rows && 
  defined $max_cols && defined $lg_dim && $lg_dim =~ m/[1-9][0-9]?/ && 
  (!defined $saturation || abs($saturation) < 100)) {
# print individual error messages
exit;
}

# continue if all req'd variables were defined and the optional variables
# were within tolerances

-- Eric P.
Sunnyvale, CA


#!/usr/bin/perl -w

use Text::Template;
use Image::Magick;
use Getopt::Long;
use File::Path;
use FindBin qw($Bin);
use POSIX;

use strict;
use vars qw($comment $directory $max_rows $max_cols $lg_dim $saturation $normal 
$last_index $indiv_template $index_template @files @html_files @old_indexes);
my $copyright = 'Copyright 2002, Fun 4-Wheel Drive Association\nPretorious Networks - 
www.Pretorious.net';

GetOptions(
'comment=s' => \$comment,
'directory=s'   => \$directory,
'rows=i'=> \$max_rows,
'cols=i'=> \$max_cols,
'largedim=i'=> \$lg_dim,
'normalize' => \$normal,
'saturation:i'  => \$saturation
);

unless (defined $directory && defined $comment && defined $max_rows && defined 
$max_cols && defined $lg_dim && $lg_dim =~ m/[1-9][0-9]?/ && (!defined $saturation || 
abs($saturation) < 100)) { 
print "Specify a directory to scan (e.g., --directory /etc)\n" unless 
$directory;
print "Provide a comment for the photos (e.g., --comment foobar)\n" unless 
$comment;
print "Specify the number of rows and columns in the indexes (e.g., --cols 5 
--rows 5)\n" unless ($max_rows && $max_cols);
print "Specify a number between -99 and 99 for the image saturation value 
(e.g., --saturation -50)\n" unless (abs($saturation) < 100);
print "Specify a number between 1 and 99 for the images\' final size as a 
percentage of the beginning size (e.g., --largedim 75)\n" unless ($lg_dim > 0 && 
$lg_dim < 100);
exit;
}

unless (-d "$Bin/$directory" or ($directory =~ m|^/| and -d $directory)) {
print "Invalid directory: $directory\nDirectory $directory must exist within 
$Bin\n";
exit;
} else {
# Strip any trailing-slashes from $directory
$directory =~ s|/$||;

opendir(DIR, $directory) or die "Could not open $directory: $!\n";
# Create an array of the image files' names
# Create a parallel array of HTML file names
# Create an array of old index-#.html files to remove
for (readdir(DIR)) {
next unless ( -f "$directory/$_");
if ((my $file_base = $_) =~ s/\.(jpg|gif)$/\.html/i) {
push (@files, $_);
push (@html_files, "$file_base.html");
next;
}
push (@old_indexes, "$directory/$_") if (m/html$/);
}
closedir(DIR) or die "Could not close $directory: $!\n";

# Calculate the number of index files to create
$last_index = ceil((scalar @files) / ($max_rows * $max_cols));

rmtree([@old_indexes, "$directory/html", "$directory/sm_images", 
"$directory/lg_images"]);
mkpath(["$directory/html", "$directory/sm_images", "$directory/lg_images"]) or 
die "Could not create subdirectories within $directory: $!";

$index_template = Text::Template->new(
TYPE=> 'FILE',
SOURCE  => "$Bin/index_template.tmpl"
);

$indiv_template = Text::Template->new(
TYPE=> 'FILE',
SOURCE  => "$Bin/indiv_template.tmpl"
);
}

my ($prev_href, $next_href, $prev_html, $next_html, $file_list, $index_hyperlist);
my $curr_index = 1;

for (my $x = 0 ; $files[$x] ; $

Re: Condition Evaluation

[eric-perl]

I found my mistake: I misread the line number in the error message. DOH!!!
The complaints were related to the block that prints individualized error
messages:


unless (defined $directory && defined $comment && defined $max_rows &&
defined $max_cols && defined $lg_dim && $lg_dim =~ m/[1-9][0-9]?/ &&
(!defined $saturation || abs($saturation) < 100)) { 

 print "Specify a directory to scan (e.g., --directory /etc)\n" unless
$directory;

 print "Provide a comment for the photos (e.g., --comment foobar)\n" 
unless $comment;

 print "Specify the number of rows and columns in the indexes (e.g., 
--cols 5 --rows 5)\n" unless ($max_rows && $max_cols);

 print "Specify a number between -99 and 99 for the image saturation value
(e.g., --saturation -50)\n" unless (abs($saturation) < 100);

 print "Specify a number between 1 and 99 for the images\' final size as a
percentage of the beginning size (e.g., --largedim 75)\n" unless
($lg_dim > 0 && $lg_dim < 100);

 exit;
}


I've added a test for "defined-ness" to the conditional statement

  print "foobar" unless (defined $foo && abs($foo) > 100)'

and everything works fine now.  Thanks for all the help!

--
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Comparison: finding if a value is gt some value AND lt another

[eric-perl]

On Fri, 27 Sep 2002, Jeff 'japhy' Pinyan wrote:
> On Sep 27, [EMAIL PROTECTED] said:
> >Is there a simple way to find if a variable's value is within a range?
> >  if (1 < $x < 5) { print 'foo'; }
> >...or do I have to join two separate comparisons using the logical AND
> >operator? e.g.,
> >  if (1 < $x and $x < 5) { print 'foo'; }
> 
> You have to do that for now.

Many thanks!

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Using map

[eric-perl]

Hello, All:

I'm having a difficult time understanding the map function.

I've got an array of file names that all end in 'jpg' or 'gif'. I'd like 
to create a parallel array of file names that end in 'html'. I'm creating 
the array this way...

@new_names = map { ($x = $_) =~ s/(jpg|gif)$/html/i; $x } @old_names;

Is there a more elegant way to accomplish this? It just doesn't seem 
elegant assigning $_ to $x, performing the substitution on $x, and then 
returning $x.

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

WHO IS NAVER-MAILER@naver.com ???

[eric-perl]

Hello, All:

Every time I send a message to this list, I receive a message from 
[EMAIL PROTECTED] immediately afterwards. It appears to be garbage 
(lots of screwy characters...).

Where is this coming from? Am I the only one receiving these?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

PerlMagick: Errors and Set(compression, comment) (fwd)

[eric-perl]

Hello, All:

I've been playin' around with IM for a few weeks now and am a bit
confused. I've installed ImageMagick and PerlMagick from RPM
(ImageMagick-5.2.7-2) on my RedHat Linux 7.1 machine and I'm attempting to
read, modify, and save JPEG files but am having trouble with this series
of commands:

1. If I use the Set method to set the comment - i.e.,
 $image->Set(comment => 'foo')
   ...no comment is set. Only $image->Comment('foo') works.

2. There doesn't seem to be any difference in file-size when calling...
  $image->Set(compression => '30')

3. Is this a "good enough" approach to capturing any errors?

<>

$im  = $image->Read(filename => "$directory/$files[$x]->{'image'}");
($height, $width) = $image->Get('height', 'width');
$im .= $image->Resize(geometry => $height * $scale . 'x' . $width * $scale);
$im .= $image->Normalize() if $normal;
$im .= $image->Modulate(saturation => $saturation + 100) if $saturation;
$im .= $image->Set(compression => 'JPEG', quality => $quality) if $quality;
$im .= $image->Comment($copyright);
$im .= $image->Write(filename => "$directory/lg_images/$files[$x]->{'image'}");
warn "$im" if $im;

<>

-- 
Eric P.
Sunnyvale, CA

<>
1. Read in a jpg image,
2. Set the comment,
3. Resize the image, and
4. Optionally... 
   a. set the compression
   b. increase the saturation
   c. normalize the saturation
5. Write the image to a new file.
<>


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Condition Evaluation

[eric-perl]

On Tue, 1 Oct 2002, Michael Fowler wrote:
> While this works, typically the way I do it is something along the lines of:
> 
> usage("Specify a directory to scan ...\n") unless defined $directory;
> usage("Provide a comment for the ...\n")   unless defined $comment;
> 
> and so on, where usage() is a subroutine that will print out the message
> specified, as well as some basic usage information.
> 
> The point being, you don't have to test the variables multiple times.  There
> is a disadvantage in that the errors will not all be printed out if there
> are multiple problems.

Thanks!

I set-out to streamline the lenthy error checking/reporting and settled on 
this:


my $err;
$err .= "Error message #1\n" unless (defined $one);
$err .= "Error message #2\n" unless (defined $two and $two eq 'foo');
$err .= "Error message #3\n" unless (defined $three and $three > 50);
die "$err" if $err;


-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Using CPAN.pm to Install Modules

[eric-perl]

Hello, All:

I'm confounded by CPAN.pm's documentation. I've already configured the 
module but can't figure out how to 'install' a module. e.g., MIME::Lite.

Starting with...

%> perl -MCPAN -e shell
cpan> i MIME/Lite

tells me that there's a distribution called MIME/Lite BUT...

cpan> install MIME/Lite

tells me that the author MIME/Lite could not be found.

How can I install this module/distribution?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Using CPAN.pm to Install Modules

[eric-perl]

On Wed, 23 Oct 2002, Jenda Krynicky wrote:
> > I'm confounded by CPAN.pm's documentation. I've already configured the
> > module but can't figure out how to 'install' a module. e.g.,
> > MIME::Lite.
>
> Try
>   cpan> install MIME::Lite

That was the first thing that I tried. CPAN complained that there were "no 
objects found of any type for argument MIME::Lite"

  cpan> i MIME/Lite

reports...

distribution id = MIME/Lite
CALLED_FORMIME/Lite

Maybe I'm using a bad mirror? CPAN is complaining that it can't find the 
file. (I'm using cloud9.net.) How can I update the list?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Using CPAN.pm to Install Modules

[eric-perl]

On Thu, 24 Oct 2002, Jenda Krynicky wrote:
> Maybe you should try a different mirror.

Is there a command to update my urllist *interactively* (just like during 
the initial configuration)? If not: Where can I find a list of mirrors?

-- 
Eric P.
Sunnyvale, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Testing for filehandles

[eric-perl]

Hello, All:

I've looked around for an answer to this (The Camel Book, The Ram Book, 
perldoc, google.com, etc.) but can't find a thing: Is it possible to test 
for the existence of a filehandle?

I've got a small script that  opens a filehandle. If that 
filehandle exists, I'd like to print to it. Otherwise, don't. e.g.,

use Getopts::Std;
getopts("n");
open(OPT_LOG,">/tmp/foo.txt") if ($opt_n);
while (<>) {
print OPT_LOG $_ if OPT_LOG;
}
close(OPT_LOG) if OPT_LOG;

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: Testing for filehandles

[eric-perl]

Tim:

I know, I know: I excluded the "or die" portion for 
readability/simplicity.

On Wed, 27 Mar 2002, Timothy Johnson wrote:
> You'd probably have better luck testing for the open() command's success

I wrote:
>> use Getopts::Std;
>> getopts("n");
>> open(OPT_LOG,">/tmp/foo.txt") if ($opt_n);
>> while (<>) {
>>  print OPT_LOG $_ if OPT_LOG;
>> }
>> close(OPT_LOG) if OPT_LOG;

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Testing for filehandles

[eric-perl]

On Wed, 27 Mar 2002, Agustin Rivera wrote:
> How would that work with use strict;? I tried it once and when I declared my
> $opt_n before using getopts, it wouldn't work.

Agustin:

>From the Getopt::Std man page:

   Note that, if your code is running under the recommended
   `use strict 'vars'' pragma, you will need to declare these
   package variables with "our":

   our($opt_foo, $opt_bar);

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Testing for filehandles

[eric-perl]

On 27 Mar 2002, Chas Owens wrote:

> Getopt::Std creates the $opt_n variables.  To use it with use strict; in
> place you must use the use vars ($opt_n); pragma as well.  or just use
> the getopts('n', \%opts); call.  Then you can say $opts{n}.

Agustin:

Also from the Getopt::Std man page:

   For those of you who don't like additional global vari-
   ables being created, getopt() and getopts() will also
   accept a hash reference as an optional second argument.
   Hash keys will be x (where x is the switch name) with key
   values the value of the argument or 1 if no argument is
   specified.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Testing for filehandles

[eric-perl]

On Wed, 27 Mar 2002, Agustin Rivera wrote:
> Ok, I've tried it both ways and it returns 1 (true) as the value.  What am I
> doing wrong?

Agustin:

1. What *exactly* do you mean "both" ways?

2. References...

>From the Getopt::Std man page:

getopt('oDI');  # -o, -D & -I take arg.  Sets opt_*...
getopts('oif:');# -o & -i are boolean flags, -f takes an argument
# Sets opt_*...

   Pass one argument which is a
   string containing all switches that take an argument.  For
   each switch found, sets $opt_x (where x is the switch
   name) to the value of the argument, or 1 if no argument.

>From "The Ram Book":

  Getop::Std also provides the getopts function which lets you specify
  whether each option is Boolean or takes a value. Arguments that take a
  value... are indicated by a ':'

In summary: 

getopts() will set BOOLEAN values OR the value supplied *if* the option 
  is followed by a ':' in the function call getopts("x:").
getopt() will set the command-line value.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: Testing for filehandles

[eric-perl]

On Wed, 27 Mar 2002, Bob Showalter wrote:
> You can pass a filehandle glob to IO::Handle::opened():

Thanks, Bob! After reading the IO::Handle man page, I decided to distill 
this approach a bit further:

  print F if fileno(F);

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Quieting 'Name "main::foo" only used once..."

[eric-perl]

Hello, All:

Is there a simple way to stop perl from complaining that a variable is 
only used once (possible typo at...)? e.g.,

  #! /usr/bin/perl -w
  use Getopts::Std;

  getopts('d');

  print "foo" if ($opt_d);

If I use 'my()' perl complains that the variable is used in a void 
context. Since I'm testing for truth, I suppose that I could set $opt_d to 
zero before calling getopts('d')...

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: Testing for filehandles

[eric-perl]

On Thu, 28 Mar 2002, Bob Showalter wrote:
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > Thanks, Bob! After reading the IO::Handle man page, I decided 
> > to distill this approach a bit further:
> > 
> >   print F if fileno(F);
> 
> Of course, that's even simpler! Just to be nitpicky, the test maybe 
> should be 
> 
>defined(fileno(F))
> 
> Since 0 is a valid file number (STDIN).

So, technically, I should be testing for "definedness" instead of "truth". 
i.e., From `perldoc -f fileno`:

  Returns the file descriptor for a filehandle, or
  undefined if the filehandle is not open.

> If you're just going to do the test on the print statement, it's
> not accomplishing all that much, since the print() will silently
> fail if the file isn't open. But a test like this would be useful
> if you want to avoid doing a lengthy operation to generate the
> data to be printed.

Printing to a non-existant filehandle (while using the -w switch)
generates a warning message:

  Filehandle main::FOO never opened at...

-- 
Eric P.
Los Gatos, CA



-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Global Variables: 'my' vs 'use vars'

[eric-perl]

Hello, All:

I've never been very good at scoping so it it's no surprise that this 
confuses me:

  When declaring variables at the beginning of a script, what is the 
  difference between 'my' and 'use vars'?

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Looping through elements of an anonymous array

[eric-perl]

Hello, All:

I have an unusual question: If I have an anonymous array stored in a hash, 
is there a more graceful way of iterating through each item in the 
anonymous array than using a counter? i.e.,

@all_records{q} = [1, 2, 3]
$j = 0;
while ($all_records{q}->[$j]) {
print $all_records{$i}->[$j];
$j++;
}

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Script execution via email

[eric-perl]

On Thu, 16 May 2002, Dan Fish wrote:
> What I'd *like* to do is be able to generate these reports "on-demand" from
> remote locations by setting up some sort of email trigger that will run the
> script when an email is sent to specially designated address and then return
> the results via email

Dan:

If you're using a Unix system, you can simply add a line to your 
/etc/aliases file (for sendmail users) or /etc/postfix/aliases file (for 
postfix users) like such:

  username: | /usr/bin/script.pl

sendmail/postfix will pipe the contents of the message to the script 
/usr/bin/script.pl when it receives an email for [EMAIL PROTECTED] 

-- 
Eric P.
Los Gatos, CA



-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: [ Something Funnie to Read ;) ]

[eric-perl]

On Thu, 16 May 2002, Bob wrote:
>   What could a url do, it isn't a document, just a link.

Two words: Code Red.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Looping through variables

[eric-perl]

Hello, All:

I'm trying to loop through a list of variables and print their values. 
e.g., print $name, $age, $phone.

What's the best way to do this? I've tried

foreach (qw(name age phone)) {
print ${$_};
}

but that doesn't seem to work.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: Looping through variables

[eric-perl]

On Fri, 17 May 2002, Mark Anderson wrote:
> It works for me (using perl 5.6.1), what seems to be the problem?  
> Why do you want to do this instead of just having three print statements?
> Are you sure that you have data in the thre variables?

FWIW: Looking back at my original script, I had declared the variables 
$name, $age, $phone *OUTSIDE*OF* the foreach loop. That's why they were 
undefined!!!

  my ($name, $age, $phone);
  foreach (qw(name age phone)) { 
print ${$_};
  }

(What a bone-head!)

Actually, what I was *trying* to do was dereference variables and pass
their values to DBI->quote() to build a string. e.g.,

  # Build the value string 'eric','34','555-1212'
  foreach ($age $name $phone) {
$values .= $dbh->quote($_) . ',';
  }
  # Remove the extra comma at the end
  chop $values;

  $dbh->do(INSERT INTO $dbfile ($column_names) VALUES ($values));

I suppose that I should just pass the variable's *value* to quote() 
instead of trying to pass the variable itself. 

Thanks!

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Looping through variables

[eric-perl]

On Sat, 18 May 2002, Michael Fowler wrote:
> Given your code above, that isn't the problem.  Where they're declared has
> no effect on the definedness; it does, however, cause compile-time errors
> when use strict is in effect.  That is not the problem you were
> encountering, though.  The variables are undefined for a very simple reason:
> you never assigned a value to them.

I could have sworn that I gave them values... Hm. That bit of code is gone 
now.

> Instead of using DBI's quote method use placeholders:
> $dbh->do(
> "INSERT INTO $dbfile ($column_names) VALUES (?, ?, ?)",
> {},
> $age, $name, $phone
> );
> It saves most of your work.  See perldoc DBI.

The quoting is necessary because many of the values that are stored 
contain white-space and punctuation. Thanks for the tip, though.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Looping through variables

[eric-perl]

FWIW: This is the solution that I finally settled upon (in full context):

$column_names = "COMPANY_NAME,JOB_TITLE,JOB_ID,URL,MAIL_TO,ATTACH,DATE";
foreach (qw(company_name job_title job_id url mail_to attach)), time) {
  # Append the quote'd parameter-value || the time-value in the list
  $new_values .= $dbh->quote(param($_) || $_) . ',';
}
# Remove the final comma from $new_values
chop $new_values;

$sth = $dbh->do("INSERT INTO $db_file ($column_names) VALUES ($new_values)")
  or die "Could not prepare statement: " . DBI->errstr;

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

SQL: Insert column?

[eric-perl]

Hello, All:

I'm using DBI.pm to interact with flat-file database and want to add a new
column to the database. Is there an SQL statement for such a task or do I 
need to transfer the contents of the file to another file and insert the 
column during the transfer?

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: DB_file help.

[eric-perl]

On 31 May 2002, Postman Pat wrote:

> I am trying to create a small database...
> 
> How would I go about storing and retrieving this information? Any examples 
> please??

Pat:

If you haven't already: Read "Programming the Perl DBI". It's actually a
quick read and does a great job of introducing the reader to database
concepts. (The book used to have a Web site - stonehenge.com - but the
site doesn't appear to be available any longer.) The DBI.pm is finicky
enough that you'll really need this reference.

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Initializing CPAN

[eric-perl]

Hello, All:

Does CPAN use http? I'm using it on a machine that has all ports except
smtp/ssh/http/https blocked. (i.e., ports 22/25/80/443 are the only open
ports)

I've just started using the CPAN module for the first time and am having
some trouble during initialization: The process dies after it attempts to
use lynx to connect to ftp://ftp.perl.org/pub/CPAN/MIRRORED.BY.gz. (It 
tries other methods to connect using ftp first too, but then dies after 
it tries lynx.) (Yes - Lynx is installed and is in the user's path.)

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

RE: Initializing CPAN

[eric-perl]

On Tue, 25 Jun 2002, Fontenot, Paul wrote:
> Let it have 20 and 21 for ftp

I poked a hole in the firewall to accept all related/established packets
coming *from* ports 20 & 21 but that didn't work. I seem to recall that
ftp actually uses two different ports for the same dialogue. Can anyone 
refresh my memory on how ftp communicates?

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

CPAN: install Bundle::CPAN

[eric-perl]

Hello, All:

This is my first time using the CPAN module.

While using CPAN to download/install a module, CPAN reported that I should
run 'install Bundle::CPAN' to get the latest stuff. When I entered 
'install Bundle::CPAN' it went about it's business getting and make'ing 
and started asking about where to install _all_kinds_of_stuff_...

What the heck is Bundle::CPAN? What is going on? It seems like it's 
installing a completely new version of Perl or something. (It wanted to 
know where my C compiler is and where it should install stuff!!!)

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: HTML::Template

[eric-perl]

On Sun, 23 Jun 2002, Shawn Bower wrote:
> <-->
> my $template = HTML::Template->new(filename=>'weather.html');
> $template->param('CurrTime', $currTime);
> $template->param('CurrTemp', $currTemp);
> $template->param('HiTemp', $hiTemp);
> $template->param('LoTemp', $loTemp);
> $template->param('ImgLoc', $imgLoc);
> $template->param('CurrCon', $currCon);
>  
> #Display template page
> print "Content-Type: text/html\n\n";
> print $template->output;

Shawn:

Where are the variables being set? e.g., 

   $imgLoc = 'foo.bar.com/images.gif';

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Re: Displaying Problems

[eric-perl]

On Tue, 25 Jun 2002 [EMAIL PROTECTED] wrote:
> Well, I still can't get my page to display.

kb:

Much earlier in this thread, I think, the fundamental point got lost:

  CGI.pm is an added layer of abstraction that creates an additional
  opportunity for users to wreak havoc.

When scipting Web app's with CGI.pm, I usually develop the HTML separately 
and then translate that into CGI.pm function calls _a_step_at_a_time_ so 
that I can catch those MINOR typos that can bring the entire script to a 
screaching halt much earlier.

As to your complaint: I recommend that you...

1. begin riping-out sections of code until the script works (so that you
   can find the almost-certainly minor typo that is causing you 
   heartburn), or

2. write a smaller script that embodies the jist of what you're trying
   to accomplish

 as most people who subscribe to this list (myself *especially*) have
neither the time nor the patience to sift through anything longer than a
screen-full of intricate code only to find insignificant errors. (e.g., 
typos)

-- 
Eric P.
Los Gatos, CA


-- 
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]