2.1.3 The mode line

At the bottom of each editor window is a mode line that provides information concerning the buffer which that window is displaying. The contents of the mode line are as follows:

• "----" or "-**-" or "-%%-": the first indicates that the buffer is unchanged since it was last saved; the second that it has been changed; and the third that it is read only.
• the name of the buffer (the name of a buffer originating from a file is usually the same as the name of that file).
• the package of the current buffer written within braces.
• a major mode (such as Fundamental or Lisp). An buffer always operates in a single major mode.
• a minor mode (such as Abbrev or Auto-Fill). If no minor mode is in operation then this element is omitted from the mode line. An editor can operate in any number of minor modes.
• a position indicator showing the line numbers of the topmost and bottommost lines displayed in the window, and the total number of lines in the buffer. The editor can be changed to count characters rather than lines, and then displays percentages rather than line numbers.
• the pathname with which the buffer is associated.