# For Perl (language) only
# Headers to use
use Scalar::Util 'looks_like_number';
# syntax
looks_like_number(<your-possible-integer>)
# example (copy-paste, and then run the following to see what happens)
use Scalar::Util 'looks_like_number';
my $iNum = "123";
if ( looks_like_number($iNum) ) {	print "$iNum is a valid integer!" . "\n";
}
else {	print "$iNum is NOT a valid integer!" . "\n";
}