>perl -wMstrict -le
"my $be24s = qq{\x11\x12\x13\x24\x25\x26\x37\x38\x39};
 my $le24s = reverse $be24s;
 printf qq{%08lx  }, $_ for unpack_be24($be24s);
 print '';
 printf qq{%08lx  }, $_ for unpack_le24($le24s);
 sub unpack_be24 {
   my ($s) = @_;
   return unpack 'N*', pack '(xa3)*', unpack '(a3)*', $s;
   }
 sub unpack_le24 {
   my ($s) = @_;
   return unpack 'V*', pack '(a3x)*', unpack '(a3)*', $s;
   }
"
00111213  00242526  00373839
00373839  00242526  00111213