12.16  If statements

“Strunk felt that the reader was in serious
  trouble most of the time, a man floundering
  in a swamp, and that it was the duty of anyone
  attempting to write English to drain the swamp
  quickly and get his man up on dry ground, or
  at least throw him a rope.”

                                                —EB White

Thou shalt not wrap useless parentheses around entire if conditions.

The canonical if statement layouts are

    if condition     action;   fi;

    if condition     action;
    else             action;
    fi;


    if condition
        #
        big expression;
    else
        big expression;
    fi;

    if condition
        #
        statement;
        statement;
        ...
    fi;

    if condition
        #
        statement;
        statement;
        ...
    else
        statement;
        statement;
        ...
    fi;

Use the most readable alternative.

Fine points:

• Put the shortest alternative first, negating the condition as necessary.
• Try to keep all indentations a multiple of four blanks.