hi,,, blazar, check out this code updates:

my $test = $b;

$test =~ s/\s+//g;

if ($test != 0) {
   $test =~ s/[1-5]//;
   print "It is either 1,2,3,4,5\n" if ! $test and $test ne "0";
}
[download]

it may seems to be lenghty for me but if you've got shorter codes for this, then you can modify it or create a better one.

What can I say? PerlPhi, please do not take this as a personal offense, I find it overly complex, clumsy, hard to parse and understand. If you really want to go the way of a regex, and I find it quite reasonable, what's wrong with the right™ one?

you may add any additional at @_ to test.

Incidentally, I wouldn't use $b as a general purpose scalar, nor @_ as a general purpose array.

well nothing is personal with it. its just a normal view if other people would see that kind of codes. okey then, the lacking with this regex:

if ($b=~/^[1-5]\z/) {
   print "\$b has to be a number and is either 1, 2, 3, 4, or 5.\n";
}
[download]

is what if $b contains:

my $b = "     5    ";
[download]

or

my $b = "   \t\t  1  \t  ";
[download]

then it wont print the message because of the whitespace. but i prefer to that codes (just add a code before "if"):

$b =~ s/\s+//g; #additional code
if ($b=~/^[1-5]\z/) {
   print "\$b has to be a number and is either 1, 2, 3, 4, or 5.\n";
}
[download]

is what if $b contains:

my $b = "     5    ";
[download]

Well, the OP explicity stated that she "would like to make sure $b has to be a digit and the digit has to be from 1 to 5". Indeed if you have different requirements and prefer to sanitize the input by removing whitespace, then you can happily do so. Your additional s is perfectly fine, in fact.