Thomas H. George wrote:
> The difficulty is in the next to last line, the 'unless ...'
> statement which causes warning:
> Use of uninitialized value in string eq at chap4-take6.pl line 49.
Some debugging hints:
1. Set the output autoflush ($|) Perl variable to a true value near the
top of your program to prevent interleaving of STDERR and STDOUT.
2. Use Data::Dumper and print() to see what's going on with your
variables/ data structures.
3. Use a debug variable to control both of the above.
4. Use Getopt::Long to read a command line option to control the debug
variable.
2009-05-02 17:34:22 dpchr...@p43400e ~
$ cat foo
#! /usr/bin/perl -w
use strict;
use Data::Dumper;
use Getopt::Long;
my $debug = 0;
GetOptions("debug|d" => \$debug)
or die "$0: error reading command line options";
$| = 1 if $debug;
my %hash = (FOO => 12345, BAR => "frunabulax", BAZ => [1,2,3]);
print Data::Dumper->Dump([\%hash], [qw(*hash)])
if $debug;
print "hello, ";
print STDERR "Ouch!\n";
print "world!\n";
2009-05-02 17:34:27 dpchr...@p43400e ~
$ ./foo
Ouch!
hello, world!
2009-05-02 17:34:43 dpchr...@p43400e ~
$ ./foo -d
%hash = (
'BAZ' => [
1,
2,
3
],
'BAR' => 'frunabulax',
'FOO' => 12345
);
hello, Ouch!
world!
Also, download and install perlindex to help you find information in the
Perl documentation:
http://search.cpan.org/~ulpfr/perlindex-1.502/perlindex.PL
HTH,
David
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