$ perl -E'
print "Enter a number or string: ";
my $s = <STDIN>;
chomp $s;
if ( $s =~ /^[0-9,.E]+$/ ) {
    say "$s is a number\n";
} else {
    say "$s may be a string\n";
}
'
Enter a number or string: ,,,
,,, is a number

$ perl -E'
print "Enter a number or string: ";
my $s = <STDIN>;
chomp $s;
if ( $s =~ /^[0-9,.E]+$/ ) {
    say "$s is a number\n";
} else {
    say "$s may be a string\n";
}
'
Enter a number or string: EEE
EEE is a number

$ perl -E'
print "Enter a number or string: ";
my $s = <STDIN>;
chomp $s;
if ( $s =~ /^[0-9,.E]+$/ ) {
    say "$s is a number\n";
} else {
    say "$s may be a string\n";
}
'
Enter a number or string: -777
-777 may be a string