MATLAB: How to draw x=2 line using plot command

plot

I want to draw the vertical line x=2. I want to draw it by using plot command in x-y plane, x-is the horizontal axis. How to draw it?

I do not want to use the following

    line([2 2], [0 10])

to draw a line from (2,0) to (2,10)

plot([2 2], [0 10])

%or maybe you want

plot([2 2],ylim)

Use the line command.

line([1,1],[0,2],'Color','k')

draws a black line from (1,0) to (1,2), for example.

doc linspace 
doc plot
doc ezplot %If you have the symbolic math toolbox

A few pointers.