Re: Use of uninitialized value in print

This demonstrates the use of the conditional and print to handle the undefined value without warning.

 
#!/usr/bin/perl
use strict;
use warnings;
use strict 'vars';
use Getopt::Std;

#Setting options
# u:username
# h:hostname
# p:password
# k:SSH Key

our ($opt_u, $opt_h, $opt_p, $opt_k);

getopts("u:h:p:k:");

#### TEST SECTION ###
print "\$opt_u=";
print $opt_u ? $opt_u : "Undefined" ;
print "\n";

print "\$opt_h=";
print $opt_h ? $opt_h : "Undefined" ;
print "\n";

print "\$opt_p=";
print $opt_p ? $opt_p : "Undefined" ;
print "\n";

print "\$opt_k=";
print $opt_k ? $opt_k : "Undefined" ;
print "\n";


$ ./test.pl 
$opt_u=Undefined
$opt_h=Undefined
$opt_p=Undefined
$opt_k=Undefined

$ ./test.pl  -u abc -h def -p ghi -k jkl                              
+   
$opt_u=abc
$opt_h=def
$opt_p=ghi
$opt_k=jkl
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Comment on Re: Use of uninitialized value in print Download Code

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Re^2: Use of uninitialized value in print by toolic (Bishop) on Mar 27, 2009 at 00:34 UTC
I have gotten into the habit of checking options using defined just in case 0 is a legal value. The code you show treats 0 as an undefined value. `$ ./test.pl -u 0 $opt_u=Undefined $opt_h=Undefined $opt_p=Undefined $opt_k=Undefined` [download] I realize that in this particular application, 0 is unlikely to be a username, password, etc., but it does not hurt to account for this corner case: `print "\$opt_u="; print defined $opt_u ? $opt_u : "Undefined" ; print "\n";` [download]	[reply] [d/l] [select]

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Re^2: Use of uninitialized value in print
by toolic (Bishop) on Mar 27, 2009 at 00:34 UTC

defined

$ ./test.pl -u 0
$opt_u=Undefined
$opt_h=Undefined
$opt_p=Undefined
$opt_k=Undefined
[download]

I realize that in this particular application, 0 is unlikely to be a username, password, etc., but it does not hurt to account for this corner case:

print "\$opt_u=";
print defined $opt_u ? $opt_u : "Undefined" ;
print "\n";
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