hi,

need to know how to use if statement at high level with explnation and example

Yasodha

The if statement is exactly what you would think. It test one value against another, then performs actions based on that test. For example, in the following script:
#!/usr/bin/ksh
x=1
if [[ $x -gt 0 ]];then
print "X is greater than 0"
else
print "X is not greater than 0"
fi

The result of that script would be "X is greater than 0" because we tested the value of x and determined it to be greater than (-gt) the value of 0.

That is the if statement at a very high level.