Shell Programming and Scripting

suppose I have data in a log file in the below format


date|time|name|email|address|SSN
date|time|name|email|address|SSN
date|time|name|email|address|SSN


is it possible to create a search engine which takes input as three filters out of which two filters should be optional?

say i give date it should list all entries for todays date...if i give date & time as input it should list all entries on that date and time...

yes.

for starters, try the grep command.
use Perl for a more sophisticated solution.

A simple grep wont help...as i told i need three filters(input patterns) out of which two should be optional

You can use something like

egrep 'pattern1|pattern2|pattern3' filename

and if pattern1 is compulsory, go for

grep pattern1 filename | egrep 'pattern2|pattern3'

You ca even go for Awk, it can give you more control over fields!!