Perl strict and "my"

[incd]

Hello,

I started out learning Perl today, but strict mode is just *weird* and not usefull? Why should I use it?

What makes $Username different than the other variables?
I was wondering, why I have to use "my ($Username)" to get this working:

#!/usr/bin/perl -w
# v1.pl
# Works as supposed and connects to the database.
use strict;
use DBI;
use DBD::mysql
 
my $Username = "a";
my $Password = "b";
my $Hostname = "c";
my $Database = "d";
 
my $dsn        = "dbi:mysql:$Database:$Hostname:3306";
my $connect    = DBI->connect($dsn, my($Username), $Password);
 
 

$ perl -c v1.pl
v1.pl syntax OK

but this doesn't work at all:

#!/usr/bin/perl -w
# v2.pl
# This one fails
use strict;
use DBI;
use DBD::mysql
 
my $Username = "a";
my $Password = "b";
my $Hostname = "c";
my $Database = "d";
 
my $dsn        = "dbi:mysql:$Database:$Hostname:3306";
my $connect    = DBI->connect($dsn, $Username, $Password);
 
 

$ perl -c v2.pl
Global symbol "$Username" requires explicit package name at v2.pl line 14.
v2.pl had compilation errors.


$ perl -v
This is perl, v5.8.8 built for x86_64-linux-gnu-thread-multi



edit: it was the missing ; after "use DBD::mysql". Sorry, my mistake.

[KevinADC]

using "strict" will help you to write good perl code. It may be hard to see how or why it does, but keep using it.