Parsing digits from command line argv - regex

Question

I want to change a perl script that executes a loop some times, and I want to pass the number of loops by command line option. The program now receives some options, then I need to change it to receive a new parameter, but it is the first time I see a perl script, then I don't know how to change.
The start of program (to parse command line options) is:
if ($#ARGV >= 1) {
for ($i = 1; $i <= $#ARGV; $i++) {
if ($ARGV[$i] =~ /^\-/) {
if ($ARGV[$i] =~ /\-test/) {
//do something
}
} else {
//do something other
}
}
}
I think that I must put something like:
if ($ARGV[$i] =~ /^\-L40/)
But it only match to 40, I don't know how to parse the number attached to the -L parameter to use for the loop limit.
Thanks in advance and sorry if there is any similar question, but I don't find any.

Answer 1

use Getopt::Long qw( );
sub usage {
print(STDERR "usage: prog [--test] [-L NUM]\n");
exit(1);
}
GetOptions(
'test' => \my $opt_test,
'L=i' => \my $opt_L,
)
or usage();
die("-L must be followed by a positive integer\n")
if defined($opt_L) && $opt_L < 1;

Answer 2

Something like:
my $loopLimit = 1; # default
if ($#ARGV >= 1)
{
for ($i = 1; $i <= $#ARGV; $i++)
{
if ($ARGV[$i] =~ /^\-/)
{
if ($ARGV[$i] =~ /\-test/)
{
# do something
}
elsif ($ARGV[$i] =~ /\-L(\d+)/) # -L followed by digits
{
$loopLimit = $1;
}
}
else
{
# do something other
}
}
}