To extract data of a perticular interval (date-time wise)

I want a shell script which extract data from a log file which contains date and time-wise data and i need the data for a perticular interval of time...what can i do???

Show us a sample of the log file, and an example of the kind of criteria you need to filter on?

07/01/08:21:45:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
07/01/08:21:46:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
07/01/08:21:47:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
07/01/08:21:48:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
07/01/08:21:49:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
07/01/08:21:50:00 72% 82% 15% 1626560 429712 878148 339500 746080 313584 592964 629668 2 314834 355136 1 355136 255400 1
e.g. i need to filter the middle two lines by date and time from the above data.

Would grep '07/01/08:21:4[78]:00' datafile be enough?