1.3 The Mode Line

Each text window’s last line is a mode line which describes what is going on in that window. When there is only one text window, the mode line appears right above the echo area. The mode line is in inverse video if the terminal supports that, starts and ends with dashes, and contains text like ‘SXEmacs: something’.

If a mode line has something else in place of ‘SXEmacs: something’, the window above it is in a special subsystem such as Dired. The mode line then indicates the status of the subsystem.

Normally, the mode line has the following appearance:

--ch-SXEmacs: buf      (major minor)----pos------

This gives information about the buffer being displayed in the window: the buffer’s name, what major and minor modes are in use, whether the buffer’s text has been changed, and how far down the buffer you are currently looking.

ch contains two stars (‘**’) if the text in the buffer has been edited (the buffer is “modified”), or two dashes (‘--’) if the buffer has not been edited. Exception: for a read-only buffer, it is ‘%%’.

buf is the name of the window’s chosen buffer. The chosen buffer in the selected window (the window that the cursor is in) is also SXEmacs’s selected buffer, the buffer in which editing takes place. When we speak of what some command does to “the buffer”, we mean the currently selected buffer. See Buffers.

pos tells you whether there is additional text above the top of the screen or below the bottom. If your file is small and it is completely visible on the screen, pos is ‘All’. Otherwise, pos is ‘Top’ if you are looking at the beginning of the file, ‘Bot’ if you are looking at the end of the file, or ‘nn%’, where nn is the percentage of the file above the top of the screen.

major is the name of the major mode in effect in the buffer. At any time, each buffer is in one and only one major mode. The available major modes include Fundamental mode (the least specialized), Text mode, Lisp mode, and C mode. See Major Modes, for details on how the modes differ and how you select one.

minor is a list of some of the minor modes that are turned on in the window’s chosen buffer. For example, ‘Fill’ means that Auto Fill mode is on. Abbrev means that Word Abbrev mode is on. Ovwrt means that Overwrite mode is on. See Minor Modes, for more information. ‘Narrow’ means that the buffer being displayed has editing restricted to only a portion of its text. This is not really a minor mode, but is like one. See Narrowing. Def means that a keyboard macro is being defined. See Keyboard Macros.

Some buffers display additional information after the minor modes. For example, Rmail buffers display the current message number and the total number of messages. Compilation buffers and Shell mode display the status of the subprocess.

If SXEmacs is currently inside a recursive editing level, square brackets (‘[…]’) appear around the parentheses that surround the modes. If SXEmacs is in one recursive editing level within another, double square brackets appear, and so on. Since information on recursive editing applies to SXEmacs in general and not to any one buffer, the square brackets appear in every mode line on the screen or not in any of them. See Recursive Edit.

SXEmacs can optionally display the time and system load in all mode lines. To enable this feature, type M-x display-time. The information added to the mode line usually appears after the file name, before the mode names and their parentheses. It looks like this:

hh:mmpm l.ll [d]

(Some fields may be missing if your operating system cannot support them.) hh and mm are the hour and minute, followed always by ‘am’ or ‘pm’. l.ll is the average number of running processes in the whole system recently. d is an approximate index of the ratio of disk activity to CPU activity for all users.

The word ‘Mail’ appears after the load level if there is mail for you that you have not read yet.

Customization note: the variable mode-line-inverse-video controls whether the mode line is displayed in inverse video (assuming the terminal supports it); nil means no inverse video. The default is t. For X frames, simply set the foreground and background colors appropriately.