Shell Programming and Scripting

HI
My doubt may be basic one but I need to get it clarified..
When i use "if" condition that checks for many AND, OR logical conditions
like

Code:

    if [[ $Set -eq 2 && $pe = "$Msg" || $pe = "$pa" || $pe = "$mat" && $port -eq 2 && $new -eq 2 && ue -eq 0 ]]; then
        return 0
    fi

Even the if condition fails it returns as zero.. Any clue..
But if i add else condition like

Code:

if [[ $Set -eq 2 && $pe = "$Msg" || $pe = "$pa" || $pe = "$mat"  && $port -eq 2 && $new -eq 2 && ue -eq 0 ]];  then
        return 0
else
       return 4
    fi

It works as expected.. But my doubt is why does if statement alone wont work??
Is it mandatory to add "else" statement in ksh shell whenever "if" is used?

dont use [[ use [ and to group your condition properly put them inside ( )

Vague question!
You haven't posted the values of those variables just before testing them. So, it is not possible to answer your question clearly.

Read about operator precedence and associativity and you should get the answer.