use File::Temp qw/tempfile/;

my ($tfh,$tfn) = tempfile(UNLINK=>1);
print $tfh <<'END_OF_SQL';
SET HEADING OFF;
SELECT systimestamp || ' IP=' || sys_context('USERENV','IP_ADDRESS') 
FROM dual;
EXIT
END_OF_SQL
close $tfh;

# the filename is in $tfn

# no "unlink" needed, that's automatic