Iam a learner of UNIX. Fortunately I got this site.
I want to check the file for its existance.

if [ ! -f filename_$Odate.dat ]
echo " Not present"
else
echo "Present"
fi

The above code is working fine. But I also want to check for the files which are compressed.
I tried the following code and it is not working:

if [ ! -f filename_$Odate.dat -o filename_$Odate.dat.Z ]
echo " Not present"
else
echo "Present"
fi

Please correct the syntax.