[11372] in Perl-Users-Digest
Perl-Users Digest, Issue: 4972 Volume: 8
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Feb 26 11:27:34 1999
Date: Fri, 26 Feb 99 08:26:19 -0800
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, 26 Feb 1999 Volume: 8 Number: 4972
Today's topics:
FAQ 9.20: How do I read mail? <perlfaq-suggestions@perl.com>
FAQ 9.21: How do I find out my hostname/domainname/IP a <perlfaq-suggestions@perl.com>
FAQ 9.22: How do I fetch a news article or the active n <perlfaq-suggestions@perl.com>
FAQ 9.2: How can I get better error messages from a CGI <perlfaq-suggestions@perl.com>
FAQ 9.3: How do I remove HTML from a string? <perlfaq-suggestions@perl.com>
Re: FAQ 9.3: How do I remove HTML from a string? <ebohlman@netcom.com>
FAQ 9.4: How do I extract URLs? <perlfaq-suggestions@perl.com>
FAQ 9.5: How do I download a file from the user's machi <perlfaq-suggestions@perl.com>
FAQ 9.6: How do I make a pop-up menu in HTML? <perlfaq-suggestions@perl.com>
FAQ 9.7: How do I fetch an HTML file? <perlfaq-suggestions@perl.com>
FAQ 9.8: How do I automate an HTML form submission? <perlfaq-suggestions@perl.com>
FAQ 9.9: How do I decode or create those %-encodings on <perlfaq-suggestions@perl.com>
file and directories <gpcu.mwagley@gcnet.com>
Re: file and directories (Greg Bacon)
Re: File Upload via HTTP progress indicator squid@fish.net
File::stat->mode? <dkoleary@tako.wwa.com>
Re: File::stat->mode? <tchrist@mox.perl.com>
Re: File::stat->mode? (Doug O'Leary)
files <singh5@students.uiuc.edu>
Re: files (Andrew M. Langmead)
Finding the week day. (Mauro Sanna)
Re: Finding the week day. (Ronald J Kimball)
Special: Digest Administrivia (Last modified: 12 Dec 98 (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 24 Feb 1999 06:46:34 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.20: How do I read mail?
Message-Id: <36d402ba@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I read mail?
Use the Mail::Folder module from CPAN (part of the MailFolder package)
or the Mail::Internet module from CPAN (also part of the MailTools
package).
# sending mail
use Mail::Internet;
use Mail::Header;
# say which mail host to use
$ENV{SMTPHOSTS} = 'mail.frii.com';
# create headers
$header = new Mail::Header;
$header->add('From', 'gnat@frii.com');
$header->add('Subject', 'Testing');
$header->add('To', 'gnat@frii.com');
# create body
$body = 'This is a test, ignore';
# create mail object
$mail = new Mail::Internet(undef, Header => $header, Body => \[$body]);
# send it
$mail->smtpsend or die;
Often a module is overkill, though. Here's a mail sorter.
#!/usr/bin/perl
# bysub1 - simple sort by subject
my(@msgs, @sub);
my $msgno = -1;
$/ = ''; # paragraph reads
while (<>) {
if (/^From/m) {
/^Subject:\s*(?:Re:\s*)*(.*)/mi;
$sub[++$msgno] = lc($1) || '';
}
$msgs[$msgno] .= $_;
}
for my $i (sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msgs)) {
print $msgs[$i];
}
Or more succinctly,
#!/usr/bin/perl -n00
# bysub2 - awkish sort-by-subject
BEGIN { $msgno = -1 }
$sub[++$msgno] = (/^Subject:\s*(?:Re:\s*)*(.*)/mi)[0] if /^From/m;
$msg[$msgno] .= $_;
END { print @msg[ sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msg) ] }
--
Weinberg's Second Law: If builders built buildings the way programmers
write programs, the first woodpecker to come along would destroy civilization.
------------------------------
Date: 24 Feb 1999 06:54:48 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.21: How do I find out my hostname/domainname/IP address?
Message-Id: <36d404a8@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I find out my hostname/domainname/IP address?
The normal way to find your own hostname is to call the ``hostname`'
program. While sometimes expedient, this has some problems, such as not
knowing whether you've got the canonical name or not. It's one of those
tradeoffs of convenience versus portability.
The Sys::Hostname module (part of the standard perl distribution) will
give you the hostname after which you can find out the IP address
(assuming you have working DNS) with a gethostbyname() call.
use Socket;
use Sys::Hostname;
my $host = hostname();
my $addr = inet_ntoa(scalar gethostbyname($host || 'localhost'));
Probably the simplest way to learn your DNS domain name is to grok it
out of /etc/resolv.conf, at least under Unix. Of course, this assumes
several things about your resolv.conf configuration, including that it
exists.
(We still need a good DNS domain name-learning method for non-Unix
systems.)
--
"Perl5, surprisingly, makes it very easy to do OO programming. I suspect
that it does this much better than Larry ever intended."
--Dean Roehrich in <1994Oct5.140720.1511@driftwood.cray.com>
------------------------------
Date: 24 Feb 1999 06:55:26 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.22: How do I fetch a news article or the active newsgroups?
Message-Id: <36d404ce@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I fetch a news article or the active newsgroups?
Use the Net::NNTP or News::NNTPClient modules, both available from CPAN.
This can make tasks like fetching the newsgroup list as simple as:
perl -MNews::NNTPClient
-e 'print News::NNTPClient->new->list("newsgroups")'
--
Basically, avoid comments. If your code needs a comment to be understood,
it would be better to rewrite it so it's easier to understand. --Rob Pike
------------------------------
Date: 23 Feb 1999 12:44:59 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.2: How can I get better error messages from a CGI program?
Message-Id: <36d3053b@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How can I get better error messages from a CGI program?
Use the CGI::Carp module. It replaces `warn' and `die', plus the normal
Carp modules `carp', `croak', and `confess' functions with more verbose
and safer versions. It still sends them to the normal server error log.
use CGI::Carp;
warn "This is a complaint";
die "But this one is serious";
The following use of CGI::Carp also redirects errors to a file of your
choice, placed in a BEGIN block to catch compile-time warnings as well:
BEGIN {
use CGI::Carp qw(carpout);
open(LOG, ">>/var/local/cgi-logs/mycgi-log")
or die "Unable to append to mycgi-log: $!\n";
carpout(*LOG);
}
You can even arrange for fatal errors to go back to the client browser,
which is nice for your own debugging, but might confuse the end user.
use CGI::Carp qw(fatalsToBrowser);
die "Bad error here";
Even if the error happens before you get the HTTP header out, the module
will try to take care of this to avoid the dreaded server 500 errors.
Normal warnings still go out to the server error log (or wherever you've
sent them with `carpout') with the application name and date stamp
prepended.
--
In general, they do what you want, unless you want consistency.
--Larry Wall in the perl man page
------------------------------
Date: 23 Feb 1999 13:45:04 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.3: How do I remove HTML from a string?
Message-Id: <36d31350@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I remove HTML from a string?
The most correct way (albeit not the fastest) is to use HTML::Parse from
CPAN (part of the HTML-Tree package on CPAN).
Many folks attempt a simple-minded regular expression approach, like
`s/<.*?>//g', but that fails in many cases because the tags may continue
over line breaks, they may contain quoted angle-brackets, or HTML
comment may be present. Plus folks forget to convert entities, like
`<' for example.
Here's one "simple-minded" approach, that works for most files:
#!/usr/bin/perl -p0777
s/<(?:[^>'"]*|(['"]).*?\1)*>//gs
If you want a more complete solution, see the 3-stage striphtml program
in
http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/striphtml.gz .
Here are some tricky cases that you should think about when picking a
solution:
<IMG SRC = "foo.gif" ALT = "A > B">
<IMG SRC = "foo.gif"
ALT = "A > B">
<!-- <A comment> -->
<script>if (a<b && a>c)</script>
<# Just data #>
<![INCLUDE CDATA [ >>>>>>>>>>>> ]]>
If HTML comments include other tags, those solutions would also break on
text like this:
<!-- This section commented out.
<B>You can't see me!</B>
-->
--
It is Unix. It is possible to overcome any number of these bogus features. --pjw
------------------------------
Date: Wed, 24 Feb 1999 02:46:38 GMT
From: Eric Bohlman <ebohlman@netcom.com>
Subject: Re: FAQ 9.3: How do I remove HTML from a string?
Message-Id: <ebohlmanF7n11r.63w@netcom.com>
Tom Christiansen <perlfaq-suggestions@perl.com> wrote:
: (This excerpt from perlfaq9 - Networking
: ($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
: part of the standard set of documentation included with every
: valid Perl distribution, like the one on your system.
: See also http://language.perl.com/newdocs/pod/perlfaq9.html
: if your negligent system adminstrator has been remiss in his duties.)
: How do I remove HTML from a string?
: The most correct way (albeit not the fastest) is to use HTML::Parse from
: CPAN (part of the HTML-Tree package on CPAN).
HTML::Parse is now deprecated in favor of HTML::Parser.
------------------------------
Date: 23 Feb 1999 14:45:07 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.4: How do I extract URLs?
Message-Id: <36d32163@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I extract URLs?
A quick but imperfect approach is
#!/usr/bin/perl -n00
# qxurl - tchrist@perl.com
print "$2\n" while m{
< \s*
A \s+ HREF \s* = \s* (["']) (.*?) \1
\s* >
}gsix;
This version does not adjust relative URLs, understand alternate bases,
deal with HTML comments, deal with HREF and NAME attributes in the same
tag, or accept URLs themselves as arguments. It also runs about 100x
faster than a more "complete" solution using the LWP suite of modules,
such as the
http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/xurl.gz
program.
--
X-Windows: Power tools for power losers.
--Jamie Zawinski
------------------------------
Date: 23 Feb 1999 15:45:09 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.5: How do I download a file from the user's machine? How do I open a file on another machine?
Message-Id: <36d32f75@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I download a file from the user's machine? How do I open a file on another machine?
In the context of an HTML form, you can use what's known as
multipart/form-data encoding. The CGI.pm module (available from CPAN)
supports this in the start_multipart_form() method, which isn't the same
as the startform() method.
--
If I allowed "next $label" then I'd also have to allow "goto $label",
and I don't think you really want that... :-) [now works in perl5!]
--Larry Wall in <1991Mar11.230002.27271@jpl-devvax.jpl.nasa.gov>
------------------------------
Date: 23 Feb 1999 16:45:11 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.6: How do I make a pop-up menu in HTML?
Message-Id: <36d33d87@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I make a pop-up menu in HTML?
Use the <SELECT> and <OPTION> tags. The CGI.pm module (available from
CPAN) supports this widget, as well as many others, including some that
it cleverly synthesizes on its own.
--
Some are born to perl, some achieve perl, and some have perl
thrust upon them.
------------------------------
Date: 23 Feb 1999 17:45:13 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.7: How do I fetch an HTML file?
Message-Id: <36d34b99@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I fetch an HTML file?
One approach, if you have the lynx text-based HTML browser installed on
your system, is this:
$html_code = `lynx -source $url`;
$text_data = `lynx -dump $url`;
The libwww-perl (LWP) modules from CPAN provide a more powerful way to
do this. They work through proxies, and don't require lynx:
# simplest version
use LWP::Simple;
$content = get($URL);
# or print HTML from a URL
use LWP::Simple;
getprint "http://www.sn.no/libwww-perl/";
# or print ASCII from HTML from a URL
# also need HTML-Tree package from CPAN
use LWP::Simple;
use HTML::Parse;
use HTML::FormatText;
my ($html, $ascii);
$html = get("http://www.perl.com/");
defined $html
or die "Can't fetch HTML from http://www.perl.com/";
$ascii = HTML::FormatText->new->format(parse_html($html));
print $ascii;
--
And don't tell me there isn't one bit of difference between null and space,
because that's exactly how much difference there is. :-)
--Larry Wall in <10209@jpl-devvax.JPL.NASA.GOV>
------------------------------
Date: 23 Feb 1999 18:45:15 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.8: How do I automate an HTML form submission?
Message-Id: <36d359ab@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I automate an HTML form submission?
If you're submitting values using the GET method, create a URL and
encode the form using the `query_form' method:
use LWP::Simple;
use URI::URL;
my $url = url('http://www.perl.com/cgi-bin/cpan_mod');
$url->query_form(module => 'DB_File', readme => 1);
$content = get($url);
If you're using the POST method, create your own user agent and encode
the content appropriately.
use HTTP::Request::Common qw(POST);
use LWP::UserAgent;
$ua = LWP::UserAgent->new();
my $req = POST 'http://www.perl.com/cgi-bin/cpan_mod',
[ module => 'DB_File', readme => 1 ];
$content = $ua->request($req)->as_string;
--
This is a "feature" of dynamic scoping when used with call-by-reference.
Don't do that. :-)
------------------------------
Date: 23 Feb 1999 19:45:17 -0700
From: Tom Christiansen <perlfaq-suggestions@perl.com>
Subject: FAQ 9.9: How do I decode or create those %-encodings on the web?
Message-Id: <36d367bd@csnews>
(This excerpt from perlfaq9 - Networking
($Revision: 1.24 $, $Date: 1999/01/08 05:39:48 $)
part of the standard set of documentation included with every
valid Perl distribution, like the one on your system.
See also http://language.perl.com/newdocs/pod/perlfaq9.html
if your negligent system adminstrator has been remiss in his duties.)
How do I decode or create those %-encodings on the web?
Here's an example of decoding:
$string = "http://altavista.digital.com/cgi-bin/query?pg=q&what=news&fmt=.&q=%2Bcgi-bin+%2Bperl.exe";
$string =~ s/%([a-fA-F0-9]{2})/chr(hex($1))/ge;
Encoding is a bit harder, because you can't just blindly change all the
non-alphanumunder character (`\W') into their hex escapes. It's
important that characters with special meaning like `/' and `?' *not* be
translated. Probably the easiest way to get this right is to avoid
reinventing the wheel and just use the URI::Escape module, which is part
of the libwww-perl package (LWP) available from CPAN.
--
In general, they do what you want, unless you want consistency.
--Larry Wall in the perl man page
------------------------------
Date: 25 Feb 1999 16:33:00 GMT
From: "Matthew Wagley" <gpcu.mwagley@gcnet.com>
Subject: file and directories
Message-Id: <01be60dc$9213df00$0200005a@training>
I know how to open a file in the same directory as I am running a perl
script, but, what if I want to open a file on a different drive or
directory or write to it?
example.
open(PROXYLOG,"c:\proxy\logs\$logproxy")
Thanks in advance for your help.
Matthew Wagley
------------------------------
Date: 25 Feb 1999 18:11:01 GMT
From: gbacon@itsc.uah.edu (Greg Bacon)
Subject: Re: file and directories
Message-Id: <7b43nl$7ev$1@info.uah.edu>
In article <01be60dc$9213df00$0200005a@training>,
"Matthew Wagley" <gpcu.mwagley@gcnet.com> writes:
: open(PROXYLOG,"c:\proxy\logs\$logproxy")
Please read Section 5 of the Perl FAQ, paying particular attention
when you read this question:
Why can't I use ""C:\temp\foo"" in DOS paths? [Why] doesn't
`C:\temp\foo.exe` work?
Greg
--
When Zarathustra had spoken these words, he again looked at the
people, and was silent. "There they stand," said he to his heart;
"there they laugh: they do not understand me; I am not the mouth for
these ears." -- Nietzsche
------------------------------
Date: Mon, 22 Feb 1999 01:35:52 GMT
From: squid@fish.net
Subject: Re: File Upload via HTTP progress indicator
Message-Id: <36d0b452.12306098@news.earthlink.net>
Shall Do...It's lookin' like a java or javascript solution is the
answer from my research
------------------------------
Date: 25 Feb 1999 23:18:08 GMT
From: "Douglas K. O'Leary" <dkoleary@tako.wwa.com>
Subject: File::stat->mode?
Message-Id: <7b4lng$fh6$1@hirame.wwa.com>
Hi;
I'm trying to get the modes off of directories in an attempt
to determine which directories are world r/w/x. I'm getting
some really squirelly results and I'm hoping someone can help.
The snippet of code below looks at the directories under
/home, which look like the following:
drwxr-xr-x 2 root root 1024 Feb 3 1998 TT_DB/
drwxr-xr-x 7 autosys sysadmin 1024 Feb 9 14:42 autosys/
drwxr-xr-x 2 dcs users 1024 Jan 12 1998 dcs/
drwxr-xr-x 2 root root 8192 Jun 10 1996 lost+found/
drwxr-xr-x 2 pdmsys pdmsys 1024 Apr 10 1998 pdmsys/
drwxr-xr-x 2 #qmaster users 1024 May 11 1998 qmaster/
drwxr-xr-x 6 #sybase sybase 1024 Oct 6 17:44 sybase/
drwxr-xr-x 2 root sys 24 Jan 18 1998 test/
drwxr-xr-x 4 training users 1024 Feb 20 1998 training/
drwxrwxrwx 10 tsdol sysadmin 1024 Feb 25 10:21 tsdol/
drwxr-xr-x 3 #tsdxc sysadmin 1024 Feb 26 1998 tsdxc/
drwxr-xr-x 2 tsecj sysadmin 24 Feb 15 10:58 tsecj/
drwxr-xr-x 2 tsjlc sysadmin 1024 Oct 6 17:44 tsjlc/
drwxr-xr-x 4 #tsjwp users 1024 Oct 6 17:44 tsjwp/
drwxr-xr-x 6 tsmxs sysadmin 1024 Jan 27 13:42 tsmxs/
drwxrwxrwx 4 tspmh sysadmin 1024 Feb 5 07:57 tspmh/
drwxrwxrwx 2 root sys 1024 Oct 6 17:44 tsrjl/
drwxr-xr-x 6 #tsrld users 1024 Mar 30 1998 tsrld/
drwx--x--x 19 tssas sysadmin 1024 Feb 10 09:36 tssas/
drwxr-xr-x 2 tssoc users 1024 Oct 6 17:44 tssoc/
drwxr-xr-x 2 tsymp sysadmin 1024 Apr 9 1998 tstmp/
Notice that three directories have 777 perms. Those are the ones
that I'm trying to ID.
The snippet of code is as follows:
#!/usr/local/bin/perl
use File::stat;
$Dir = "/home";
opendir (Dir,"$Dir") or die "Can't open $Dir - ($!)";
@files = readdir(Dir);
foreach $file (sort @files)
{ if ( -d "$Dir/$file" && $file ne "." && $file ne "..")
{ $st = stat ("$Dir/$file");
if ($st->mode & 0007)
{ print "$Dir/$file is wide open\n"; }
else
{ print "$Dir/$file is not wide open\n"; }
}
}
when compiled and run, it reports that everything is
wide open. I got the mode out of sys/stat.h file; the only
thing I can figure is that I got it wrong; however, the
line seems fairly self explanatory.
Anyone have any hints?
Thanks!
Doug O'Leary
--
--------------------
Douglas K. O'Leary
Senior System Admin
dkoleary@mayspeh.com
dkoleary@wwa.com
--------------------
------------------------------
Date: 25 Feb 1999 16:49:25 -0700
From: Tom Christiansen <tchrist@mox.perl.com>
Subject: Re: File::stat->mode?
Message-Id: <36d5e185@csnews>
[courtesy cc of this posting sent to cited author via email]
In comp.lang.perl.misc,
"Douglas K. O'Leary" <dkoleary@tako.wwa.com> writes:
: if ($st->mode & 0007)
: { print "$Dir/$file is wide open\n"; }
: else
: { print "$Dir/$file is not wide open\n"; }
The logic is wrong. x&y is true if any bits are shared
in common. Perhaps you mean (x&y) == y.
--tom
--
"I think the pod should be the master...."
--Larry Wall in <9410072305.AA03994@scalpel.netlabs.com>
------------------------------
Date: Thu, 25 Feb 1999 21:25:50 -0600
From: dkoleary@wwa.com (Doug O'Leary)
Subject: Re: File::stat->mode?
Message-Id: <MPG.113fd0355227c46898968e@news.wwa.com>
[This followup was posted to comp.lang.perl.misc and a copy was sent to
the cited author.]
In article <36d5e185@csnews>, tchrist@mox.perl.com says...
> The logic is wrong. x&y is true if any bits are shared
> in common. Perhaps you mean (x&y) == y.
>
>
>
More to the point, that's what I was looking for. Although I've been
programming off and on in a variety of languages for a number years, bit
math has never been something that came easy for me. I took the logic
out of the man page for the File::stat module (which, if memory serves,
you wrote?). The example that I tried to emulate said something like
(forgive me if I'm butchering it, this is from memory):
use File::stat;
$st = stat($file);
if ($st->mode & 0111 && $st->nlink > 1)
{ print "$file is executable and has a whole bunch -o links\n"; }
Off subject, but still important: Thanks for the time and effort you put
into your books and posts. I'm assuming you get paid something for the
books that you write; however, you more than likely don't for the posts.
I certainly appreciate your efforts.
Doug O'Leary
--
==============
Douglas K. O'Leary
Senior System Admin
dkoleary@wwa.com
doleary@ms.acxiom.com
==============
------------------------------
Date: Mon, 22 Feb 1999 10:12:06 -0600
From: Vivek Singh <singh5@students.uiuc.edu>
Subject: files
Message-Id: <36D181D5.F327430D@students.uiuc.edu>
Hi- I am a total dumber in PERL programming and want to do some really
easy stuff. Hopefully someone can help me out.
MY PROBLEM
I have 200 files, each file has same headings but different length. For
example the there are 4 headings in each file namely A,B,C & D. Now I
want to extract all text from heading B for all files and write them in
ONE output file.
Please let me know if you ever came accross such code and I would be
very pleased to recieve a code that can handle it.
Thank you in advance,
Vivek.
------------------------------
Date: Mon, 22 Feb 1999 21:19:51 GMT
From: aml@world.std.com (Andrew M. Langmead)
Subject: Re: files
Message-Id: <F7Kr93.ECs@world.std.com>
Vivek Singh <singh5@students.uiuc.edu> writes:
>I have 200 files, each file has same headings but different length. For
>example the there are 4 headings in each file namely A,B,C & D. Now I
>want to extract all text from heading B for all files and write them in
>ONE output file.
What does a header look like and what does the data under a heading
look like. Do you want the output to be sequential (all the data under
heading B from file 1, then all the data under heading B from file 2,
etc.) or intermixed (line 1 under heading B from file 1, then line 1
from heading B from file 2, etc.)
I think basically what you want would be something that would do this,
(in pseudocode)
for each file
open the file
for each line of the file
if the current line is the header you are searching for
for each line of the file
if the line is the start of a new header
skip the rest of this file, and start on the next one
otherwise
print this line
end if the line is a header
end for each line
end if this line is the header you are searching for
end for each line of the file
end for each file
Converting this to perl would make it look like this:
#for each file
FILE: for my $file (@ARGV) {
# open the file
open FILE, $file or die "Can't open $file: $!\n";
# for each line of the file
while(<FILE>) {
# if the current line is the header you are searching for
#
## ??? What goes here ???
#
if(/some-pattern-that-matches-heading-b/) {
# for each line of the file
while(<FILE>) {
# if the line is the start of a new header
#
## ??? What goes here ???
#
if(/some-pattern-that-matches-heading-c/) {
# skip the rest of this file, and start on the next one
next FILE;
# otherwise
}
else {
# print this line
print;
# end if the line is a header
}
# end for each line
}
# end if this line is the header you are searching for
}
# end for each line of the file
}
#end for each file
}
So just figure out how to tell the difference between a header and a
non-header, and fill in the blanks.
--
Andrew Langmead
------------------------------
Date: 23 Feb 1999 22:07:57 GMT
From: mauro@msan. (Mauro Sanna)
Subject: Finding the week day.
Message-Id: <7av8rt$n3f$1@nslave1.tin.it>
Hi.
Sorry for my bad english, I'm Italian.
I have a great problem.
I can't find the week day of a date.
For example, how can I get the week day of 12/02/1999?
Thanks.
--
per rispondere togli <toglimi> dall'indirizzo di posta.
------------------------------
Date: Tue, 23 Feb 1999 21:47:10 -0500
From: rjk@linguist.dartmouth.edu (Ronald J Kimball)
Subject: Re: Finding the week day.
Message-Id: <1dnp736.1as7tc41aqh2f1N@bay1-193.quincy.ziplink.net>
Mauro Sanna <mauro@msan.> wrote:
> I can't find the week day of a date.
> For example, how can I get the week day of 12/02/1999?
I remember seeing this question less than a month ago...
(And less than a month before that.)
Here's the answer I gave, archived by DejaNews:
http://www.dejanews.com/getdoc.xp?AN=431502321
:-)
--
_ / ' _ / - aka - rjk@linguist.dartmouth.edu
( /)//)//)(//)/( Ronald J Kimball chipmunk@m-net.arbornet.org
/ http://www.ziplink.net/~rjk/
"It's funny 'cause it's true ... and vice versa."
------------------------------
Date: 12 Dec 98 21:33:47 GMT (Last modified)
From: Perl-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Special: Digest Administrivia (Last modified: 12 Dec 98)
Message-Id: <null>
Administrivia:
Well, after 6 months, here's the answer to the quiz: what do we do about
comp.lang.perl.moderated. Answer: nothing.
]From: Russ Allbery <rra@stanford.edu>
]Date: 21 Sep 1998 19:53:43 -0700
]Subject: comp.lang.perl.moderated available via e-mail
]
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------------------------------
End of Perl-Users Digest V8 Issue 4972
**************************************
