#### 2.7.3 Comments and the Help System

The `help` command (see Getting Help) is able to find the first block of comments in a function and return those as a documentation string. This means that the same commands used to get help on built-in functions are available for properly formatted user-defined functions. For example, after defining the function `f` below,

    function xdot = f (x, t)

    # usage: f (x, t)
    #
    # This function defines the right-hand
    # side functions for a set of nonlinear
    # differential equations.

      r = 0.25;
      …
    endfunction

the command `help f` produces the output

     usage: f (x, t)

     This function defines the right-hand
     side functions for a set of nonlinear
     differential equations.

Although it is possible to put comment lines into keyboard-composed, throw-away Octave programs, it usually isn’t very useful because the purpose of a comment is to help you or another person understand the program at a later time.

The `help` parser currently only recognizes single line comments (see Single Line Comments) and not block comments for the initial help text.