[6510] in Perl-Users-Digest
Perl-Users Digest, Issue: 135 Volume: 8
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Mon Mar 17 20:17:31 1997
Date: Mon, 17 Mar 97 17:00:19 -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 Mon, 17 Mar 1997 Volume: 8 Number: 135
Today's topics:
Re: array of filehandles ...how to? (Michael Fuhr)
Re: Can't open file (Eric Bohlman)
Re: Can't open file (Tad McClellan)
Odd behavior with numbers (Nicholas J. Leon)
Perl FAQ Table of Contents <tchrist@mox.perl.com>
Perl programmers wanted, NYC, short or long-term positi (Pigbert)
Re: Unix vs WIN95 equivalents (Eric Bohlman)
Digest Administrivia (Last modified: 8 Mar 97) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 17 Mar 1997 17:27:58 -0700
From: mfuhr@dimensional.com (Michael Fuhr)
Subject: Re: array of filehandles ...how to?
Message-Id: <5gknie$a2n@nova.dimensional.com>
Richard Moss <rjm@theory.chem.ubc.ca> writes:
>I'd like to open and use and array of filehandles, but can't figure out
>how to (ahh - I havent' used references much before ;-)
This is answered in the Perl FAQ:
http://www.perl.com/perl/faq/
Look in section 5, "Files and Formats".
--
Michael Fuhr
http://www.dimensional.com/~mfuhr/
------------------------------
Date: Tue, 18 Mar 1997 00:01:21 GMT
From: ebohlman@netcom.com (Eric Bohlman)
Subject: Re: Can't open file
Message-Id: <ebohlmanE77pE9.DJy@netcom.com>
Stuart Wildish (swildish@pine.shu.ac.uk) wrote:
: I've got this script that, well, it's going to do lots of stuff, but at
: the moment I can't even get it to open a file. Here's the relevent code
: :
: #!/usr/local/bin/perl
Where's your "-w"?
: $database_filename = "/usr/local/httpd/cgi-bin/mploy-database.txt";
[snip]
: sub search
: {
: open (FILE, $database_location) || print "can't open sodding file";
It really helps if the main program and the subroutine can agree on the
name of the variable that holds the filename...
------------------------------
Date: Mon, 17 Mar 1997 17:49:11 -0600
From: tadmc@flash.net (Tad McClellan)
Subject: Re: Can't open file
Message-Id: <n9lkg5.n64.ln@localhost>
Stuart Wildish (swildish@pine.shu.ac.uk) wrote:
: I've got this script that, well, it's going to do lots of stuff, but at
: the moment I can't even get it to open a file. Here's the relevent code
: :
: #!/usr/local/bin/perl
Hey. Where is that -w to enable compiler warnings?
I expect perl itself would have helped you with this problem,
if you had only asked it to...
: $database_filename = "/usr/local/httpd/cgi-bin/mploy-database.txt";
: print "Content-type: text/plain", "\n\n";
: if ( defined ($database_filename) && (-e $database_filename) ) {
: print "Datafile defined and exists.", "\n";
: } else {
: print "Bollocks!", "\n";
: }
: if ($FORM{for}) {
: print "You put: ", $FORM{for}, "\n";
: &search();
:
: }
: exit(0);
: sub search
: {
: open (FILE, $database_location) || print "can't open sodding file";
^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^
Where does this variable get set?
maybe you meant $database_filename ??
You should ALWAYS have the error message give you some helpful
debugging information, rather than some cutesy message that doesn't
help much:
open (FILE, $database_location) ||
print "can't open '$database_location' file $!";
^^^^^^^^^^^^^^^^^^ ^^
Now, when it fails, you know what filename it was trying, and
what the OS had to say about the failure...
:
: while (<FILE>) {
: print "hello!", "\n";
:
: }
: close (FILE);
: }
: I can't see what's wrong with it at all, so any help would be much
: appreciated (sp?)
--
Tad McClellan SGML Consulting
Tag And Document Consulting Perl programming
tadmc@flash.net
------------------------------
Date: 17 Mar 1997 21:01:29 GMT
From: nicholas@neko.binary9.net (Nicholas J. Leon)
Subject: Odd behavior with numbers
Message-Id: <slrn5irc8o.18.nicholas@neko.binary9.net>
I was doing some playing around and I found an interesting effect. It
is demonstrated with this little snippet of code:
#!/usr/bin/perl
$a=sprintf("%.1f",1/3);
$a-=.1;
print "a is $a.\n";
$a-=.1;
print "a is $a.\n";
$a-=.1;
print "a is $a.\n";
$a-=.1;
print "a is $a.\n";
which outputs:
a is 0.2.
a is 0.1.
a is -2.77555756156289e-17.
a is -0.1.
???
Summary of my perl5 (5.0 patchlevel 3 subversion 0) configuration:
Platform:
osname=solaris, osver=2.4, archname=sparc-solaris
uname='sunos peacock 5.4 generic sun4m sparc '
hint=recommended, useposix=true, d_sigaction=define
Compiler:
cc='gcc', optimize='-O', gccversion=2.7.0
cppflags='-I/usr/local/include'
ccflags ='-I/usr/local/include'
stdchar='unsigned char', d_stdstdio=define, usevfork=false
voidflags=15, castflags=0, d_casti32=define, d_castneg=define
intsize=4, alignbytes=8, usemymalloc=y, randbits=15
Linker and Libraries:
ld='gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib
libs=-lsocket -lnsl -ldl -lm -lc -lcrypt
libc=/lib/libc.so, so=so
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=, ccdlflags=' '
cccdlflags='-fpic', lddlflags='-G -L/usr/local/lib'
@INC: /usr2/people/nicholas/lib
/usr/local/lib/perl5/sparc-solaris/5.003 /usr/local/lib/perl5
/usr/local/lib/perl5/site_perl/sparc-solaris
/usr/local/lib/perl5/site_perl .
--
N!
------------------------------------------------------------------------------
Nicholas J. Leon <nicholas@binary9.net>
"Elegance through Simplicity" http://www.binary9.net/nicholas
SF/F Reading Suggestion #3: Magic of Recluse by L.E. Modesitt, Jr.
------------------------------
Date: 17 Mar 1997 23:47:13 GMT
From: Tom Christiansen <tchrist@mox.perl.com>
Subject: Perl FAQ Table of Contents
Message-Id: <5gkl61$fpo$5@csnews.cs.colorado.edu>
PART 0:
Where to get this document
How to contribute to this document
What will happen if you mail your Perl programming
problems to the authors
Credits
Author and Copyright Information
Non-commercial Reproduction
Commercial Reproduction
Disclaimer
Changes
PART 1:
What is Perl?
Who supports Perl? Who develops it? Why is it free?
Which version of Perl should I use?
What are perl4 and perl5?
How stable is Perl?
Is Perl difficult to learn?
How does Perl compare with other languages like Java,
Python, REXX, Scheme, or Tcl?
Can I do [task] in Perl?
When shouldn't I program in Perl?
What's the difference between "perl" and "Perl"?
Is it a Perl program or a Perl script?
What is a JAPH?
Where can I get a list of Larry Wall witticisms?
How can I convince my sysadmin/supervisor/employees to
use version (5/5.004/Perl instead of some other language)?
PART 2:
What machines support Perl? Where do I get it?
How can I get a binary version of Perl?
I copied the Perl binary from one machine to another,
but scripts don't work.
I grabbed the sources and tried to compile but gdbm/dynamic
loading/malloc/linking/... failed. How do I make it work?
What modules and extensions are available for Perl?
What is CPAN? What does CPAN/src/... mean?
Is there an ISO or ANSI certified version of Perl?
Where can I get information on Perl?
What are the Perl newsgroups on USENET? Where do I
post questions?
Where should I post source code?
Perl Books
Perl in Magazines
Perl on the Net: FTP and WWW Access
What mailing lists are there for perl?
Archives of comp.lang.perl.misc
Perl Training
Where can I buy a commercial version of Perl?
Where do I send bug reports?
What is perl.com? perl.org? The Perl Institute?
How do I learn about object-oriented Perl programming?
PART 3:
How do I do (anything)?
How can I use Perl interactively?
Is there a Perl shell?
How do I debug my Perl programs?
How do I profile my Perl programs?
How do I cross-reference my Perl programs?
Is there a pretty-printer (formatter) for Perl?
Is there a ctags for Perl?
Where can I get Perl macros for vi?
Where can I get perl-mode for emacs?
How can I use curses with Perl?
How can I use X or Tk with Perl?
How can I generate simple menus without using CGI or Tk?
Can I dynamically load C routines into Perl?
What is undump?
How can I make my Perl program run faster?
How can I make my Perl program take less memory?
Is it unsafe to return a pointer to local data?
How can I free an array or hash so my program shrinks?
How can I make my CGI script more efficient?
How can I hide the source for my Perl program?
How can I compile my Perl program into byte-code or C?
How can I get '#!perl' to work on [MSDOS,NT,...]?
Can I write useful perl programs on the command line?
Why don't perl one-liners work on my DOS/Mac/VMS system?
Where can I learn about CGI or Web programming in Perl?
Where can I learn about object-oriented Perl programming?
Where can I learn about linking C with Perl? [h2xs, xsubpp]
I've read perlembed, perlguts, etc., but I can't embed perl
in my C program, what am I doing wrong?
When I tried to run my script, I got this message. What
does it mean?
What's MakeMaker?
PART 4:
Why isn't my octal data interpreted correctly?
Does perl have a round function? What about ceil()
and floor()? Trig functions?
How do I convert bits into ints?
How do I multiply matrices?
How do I perform an operation on a series of integers?
How can I output Roman numerals?
Why aren't my random numbers random?
How do I find the week-of-the-year/day-of-the-year?
How can I compare two date strings?
How can I take a string and turn it into epoch seconds?
How can I find the Julian Day?
Does Perl have a year 2000 problem?
How do I validate input?
How do I unescape a string?
How do I remove consecutive pairs of characters?
How do I expand function calls in a string?
How do I find matching/nesting anything?
How do I reverse a string?
How do I expand tabs in a string?
How do I reformat a paragraph?
How can I access/change the first N letters of a string?
How do I change the Nth occurrence of something?
How can I count the number of occurrences of a substring
within a string?
How do I capitalize all the words on one line?
How can I split a [character] delimited string except
when inside [character]? (Comma-separated files)
How do I strip blank space from the beginning/end of a string?
How do I extract selected columns from a string?
How do I find the soundex value of a string?
How can I expand variables in text strings?
What's wrong with always quoting "$vars"?
Why don't my <<HERE documents work?
What is the difference between $array[1] and @array[1]?
How can I extract just the unique elements of an array?
How can I tell whether an array contains a certain element?
How do I compute the difference of two arrays? How do
I compute the intersection of two arrays?
How do I find the first array element for which a condition
is true?
How do I handle linked lists?
How do I handle circular lists?
How do I shuffle an array randomly?
How do I process/modify each element of an array?
How do I select a random element from an array?
How do I permute N elements of a list?
How do I sort an array by (anything)?
How do I manipulate arrays of bits?
Why does defined() return true on empty arrays and hashes?
How do I process an entire hash?
What happens if I add or remove keys from a hash while
iterating over it?
How do I look up a hash element by value?
How can I know how many entries are in a hash?
How do I sort a hash (optionally by value instead of key)?
How can I always keep my hash sorted?
What's the difference between "delete" and "undef" with hashes?
Why don't my tied hashes make the defined/exists distinction?
How do I reset an each() operation part-way through?
How can I get the unique keys from two hashes?
How can I store a multidimensional array in a DBM file?
How can I make my hash remember the order I put elements into it?
Why does passing a subroutine an undefined element in a hash
create it?
How can I make the Perl equivalent of a C structure/C++
class/hash or array of hashes or arrays?
How can I use a reference as a hash key?
How do I handle binary data correctly?
How do I determine whether a scalar is a
number/whole/integer/float?
How do I keep persistent data across program calls?
How do I print out or copy a recursive data structure?
How do I define methods for every class/object?
How do I verify a credit card checksum?
PART 5:
How do I flush/unbuffer a filehandle? Why must I do this?
How do I change one line in a file/delete a line in
a file/insert a line in the middle of a file/append to
the beginning of a file?
How do I count the number of lines in a file?
How do I make a temporary file name?
How can I manipulate fixed-record-length files?
How can I make a filehandle local to a subroutine? How do I
pass filehandles between subroutines? How do I make
an array of filehandles?
How can I set up a footer format to be used with write()?
How can I write() into a string?
How can I output my numbers with commas added?
How can I translate tildes (~) in a filename?
How come when I open the file read-write it wipes it out?
Why do I sometimes get an "Argument list too long" when I use <*>?
Is there a leak/bug in glob()?
How can I open a file with a leading "E<gt>" or trailing blanks?
How can I reliably rename a file?
How can I lock a file?
What can't I just open(FH, ">file.lock")?
I still don't get locking. I just want to increment the number
in the file. How can I do this?
How do I randomly update a binary file?
How do I get a file's timestamp in perl?
How do I set a file's timestamp in perl?
How do I print to more than one file at once?
How can I read in a file by paragraphs?
How can I read a single character from a file? From the keyboard?
How can I tell if there's a character waiting on a filehandle?
How do I open a file without blocking?
How do I create a file only if it doesn't exist?
How do I do a C<tail -f> in perl?
How do I dup() a filehandle in Perl?
How do I close a file descriptor by number?
Why can't I use "C:\temp\foo" in DOS paths? What
doesn't `C:\temp\foo.exe` work?
Why doesn't glob("*.*") get all the files?
Why does Perl let me delete read-only files? Why
does C<-i> clobber protected files? Isn't this
a bug in Perl?
How do I select a random line from a file?
PART 6:
How can I hope to use regular expressions without
creating illegible and unmaintainable code?
I'm having trouble matching over more than one
line. What's wrong?
How can I pull out lines between two patterns that
are themselves on different lines?
I put a regular expression into $/ but it didn't
work. What's wrong?
How do I substitute case insensitively on the LHS, but
preserving case on the RHS?
How can I make C<\w> match accented characters?
How can I match a locale-smart version of C</[a-zA-Z]/>?
How can I quote a variable to use in a regexp?
What is C</o> really for?
How do I use a regular expression to strip C style
comments from a file?
Can I use Perl regular expressions to match balanced text?
What does it mean that regexps are greedy? How can I
get around it?
How do I process each word on each line?
How can I print out a word-frequency or line-frequency summary?
How can I do approximate matching?
How do I efficiently match many regular expressions at once?
Why don't word-boundary searches with C<\b> work for me?
Why does using $&, $`, or $' slow my program down?
What good is C<\G> in a regular expression?
Are Perl regexps DFAs or NFAs? Are they POSIX compliant?
What's wrong with using grep or map in a void context?
How can I match strings with multi-byte characters?
PART 7:
Can I get a BNF/yacc/RE for the Perl language?
What are all these $@%* punctuation signs, and how do I
know when to use them?
Do I always/never have to quote my strings or use semicolons
and commas?
How do I skip some return values?
How do I temporarily block warnings?
What's an extension?
Why do Perl operators have different precedence than C operators?
How do I declare/create a structure?
How do I create a module?
How do I create a class?
How can I tell if a variable is tainted?
What's a closure?
How can I pass/return a {Function, FileHandle, Array, Hash,
Method, Regexp}?
How do I create a static variable?
What's the difference between dynamic and lexical (static)
scoping? Between local() and my()?
How can I access a dynamic variable while a similarly
named lexical is in scope?
What's the difference between deep and shallow binding?
Why doesn't "local($foo) = <FILE>;" work right?
How do I redefine a built-in function, operator, or method?
What's the difference between calling a function
as &foo and foo()?
How do I create a switch or case statement?
How can I catch accesses to undefined variables/functions/methods?
Why can't a method included in this same file be found?
How can I find out my current package?
PART 8:
How do I find out which operating system I'm running under?
How come exec() doesn't return?
How do I do fancy stuff with the keyboard/screen/mouse?
How do I ask the user for a password?
How do I read and write the serial port?
How do I decode encrypted password files?
How do I start a process in the background?
How do I trap control characters/signals?
How do I modify the shadow password file on a Unix system?
How do I set the time and date?
How can I sleep() or alarm() for under a second?
How can I measure time under a second?
How can I do an atexit() or setjmp()/longjmp()? (Exception
handling)
Why doesn't my sockets program work under System V (Solaris)?
What does the error message "Protocol not supported" mean?
How can I call my system's unique C functions from Perl?
Where do I get the include files to do ioctl() or syscall()?
Why do setuid perl scripts complain about kernel problems?
How can I open a pipe both to and from a command?
How can I capture STDERR from an external command?
Why doesn't open() return an error when a pipe open fails?
What's wrong with using backticks in a void context?
How can I call backticks without shell processing?
Why can't my script read from STDIN after I
gave it EOF (^D on Unix, ^Z on MSDOS)?
How can I convert my shell script to perl?
Can I use perl to run a telnet or ftp session?
How can I write expect in Perl?
Is there a way to hide perl's command line from
programs such as "ps"?
I {changed directory, modified my environment} in a perl
script. How come the change disappeared when I exited
the script? How do I get my changes to be visible?
How do I close a process's filehandle without waiting for
it to complete?
How do I fork a daemon process?
How do I make my program run with sh and csh?
How do I keep my own module/library directory?
How do I find out if I'm running interactively or not?
How do I timeout a slow event?
How do I set CPU limits?
How do I avoid zombies on a Unix system?
How do I use an SQL database?
How do I make a system() exit on control-C?
How do I open a file without blocking?
How do I install a CPAN module?
PART 9:
My CGI script runs from the command line but not the
browser. Can you help me fix it?
How do I remove HTML from a string?
How do I extract URLs?
How do I download a file from the user's machine? How
do I open a file on another machine?
How do I make a pop-up menu in HTML?
How do I fetch an HTML file?
how do I decode or create those %-encodings on the web?
How do I redirect to another page?
How do I put a password on my web pages?
How do I edit my .htpasswd and .htgroup files with Perl?
How do I parse an email header?
How do I decode a CGI form?
How do I check a valid email address?
How do I decode a MIME/BASE64 string?
How do I return the user's email address?
How do I send/read mail?
How do I find out my hostname/domainname/IP address?
How do I fetch a news article or the active newsgroups?
How do I fetch/put an FTP file?
How can I do RPC in Perl?
--
Tom Christiansen tchrist@jhereg.perl.com
X-Windows: A mistake carried out to perfection.
--Jamie Zawinski
------------------------------
Date: 17 Mar 1997 19:58:16 -0500
From: piglet@panix.com (Pigbert)
Subject: Perl programmers wanted, NYC, short or long-term positions available
Message-Id: <5gkpb8$6dh@panix.com>
PROGRAMMERS WANTED FOR BEST OF BREED INTERNET/INTRANET APPLICATION
Evolution Online Systems, one of New York's original Internet pioneers,
is seeking candidates interested in joining our team of a highly skilled
and dedicated group of professional consultants and developers. We enjoy
an excellent working environment, we only work on projects which excite
us and we've been in business for close to 5 years, so we must be doing
something right.
We are currently working on a cutting edge Intranet application for a
large and prestigious client which includes creating a web application
development architecture. Both short-term (2-3 month) and permanent
positions available on this project. Salary range is $50K to $70K
depending on skills and experience.
You must have 2 years experience developing application software, and
must have development experience in at least two different high level
languages. Must be familiar with Unix, preferably several variants.
LISP or Scheme experience a plus.
To find out more about working with us, please send a resume or
introductory letter to jobs@evolution.com, or call us at 212-843-5535.
--
____
Piglet \bi/ http://www.evolution.com/ Now hiring!
piglet@piglet.org \/ Please don't feed or tease the kooks.
------------------------------
Date: Mon, 17 Mar 1997 23:30:33 GMT
From: ebohlman@netcom.com (Eric Bohlman)
Subject: Re: Unix vs WIN95 equivalents
Message-Id: <ebohlmanE77nyy.BpI@netcom.com>
Mark Miller (M.P.Miller@worldnet.att.net) wrote:
: I am using the llama book and am having difficulty finding any kind of documentation
: explaining equivalent keystrokes between Unix and WIN95. As an example, on page 65, it
: explains how to end a manually entered array: press "Control-D" and then the script
: will continue. This combination does not work in WIN95. Instead, I've had to use the
: following:
[please keep your line lengths below 80 characters]
In Win95 and DOS, Control-Z is the end-of-file character.
------------------------------
Date: 8 Mar 97 21:33:47 GMT (Last modified)
From: Perl-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 8 Mar 97)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V8 Issue 135
*************************************
