带有文本x轴的书写条形图。

I was wondering how I can make a simple bar chart that perhaps has day as the x-axis, with values 'today' and 'yesterday', and the y-axis as perhaps 'time' with corresponding values '1' and '2'. I guess I'm confused as to how to set text as the values for the x-axis, how to show the y axis, and what exactly r.g.axis does... (I found an example using I was wondering how I can make a simple bar cha