Shell Programming and Scripting

Create a script to do the following :
a. Poll for ctl file abc.ctl
b. if the ctl file is found, then check for corresponding dat file(abc.dat)
c. if dat file is not found then fail the process
e. if dat file is found do file validation
File Validation:
a. Check the stability of file.
b. Check that the date in the ctl file and dat file match.
c. check that no two rows in the file are duplicate. if Duplicate exists fail the process.
Logging:
Log all the events in a log file

What have you tried so far, and where are you stuck?

I'm asking this because this is a site where you can ask for whelp with problems, not complete solutions.