Have you read the documentation of Time::gmtime? It returns a blessed Time::tm object, which is stringified when you print it.

To obtain what you want, use the methods provided by the object, as in:

use Time::gmtime;

my $tm = gmtime();

print $tm->sec;
print $tm->min;
# etc...
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Read perldoc Time::gmtime, all the info you need is in it.