jQuery plugin to toggle truncated text
all of your indentation makes it very difficult to read the code, this is what your code should look like.  you were also missing a Semi-Colon after return false

$.fn.vishTrunc = function(options) {
    var settings = $.extend({
            size: 100,
            omission: '...',
        }, options);

    return this.each(function() {
        var elements = $(this),
            regex    = /\s+/,
            init     = function() {
                elements.each(function() {
                    var textDefault = $(this).text();
                    if (textDefault.length &gt; settings.size) {
                        var words = textDefault.trim().split(regex).slice(0,settings.size);
                        var replacement = $("&lt;p class='replacement'/&gt;").text(words.join(" ") + settings.omission);

                        $(this).parent().find('.read-more').click(function(){   
                            if($(this).text() === 'Read More'){
                                replacement.hide();
                                $(this).parent().find('p:eq(1)').show();    
                            } else if($(this).text() === 'Read Less'){
                                replacement.show();
                                $(this).parent().find('p:eq(1)').hide();
                            }

                            $(this).text(function(i,old){
                                return old==='Read More' ?  'Read Less' : 'Read More';
                            });

                            return false;
                        });

                        $(this).before(replacement);
                        $(this).hide();

                    }
                });
            };
        init();
    });
};


Personally, I think this is a lot of indentation and a lot of nested functions.  

I think that you should break out the functions, this would reduce the amount of nesting and help document what each function is doing by giving them names.