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aoeui − a lightweight visual editor optimized for the Dvorak keyboard


aoeui [ -s ] [ -t tab stop ] [ -u | -U ] [file...]


aoeui is an interactive display text editor optimized for users of the Dvorak keyboard layout.

When run with no file name arguments, aoeui displays a short command introduction and summary.

aoeui can browse very large read-only files with quick start-up, since original texts are memory-mapped from files and not duplicated in memory until they are about to be modified.



Use spaces, never tabs, for automatic indentation.

-t 8

Set the tab stop to 8, or to an unreasonable value. This setting can be overridden on a per-text basis later.


Treat files as UTF-8 even if they contain invalid UTF-8 encodings.


Don’t treat files as UTF-8 even if they look like it.


aoeui has no embedded extension language, since it is trivial to pass regions of text from the editor to any program or script that can read standard input and write standard output. The shell, sed(1), awk(1), python(1), and perl(1) are all usable for such scripting. Further, since aoeui ships will full sources and the rights to modify it, users can customize it directly.

The editor has no syntax highlighting modes, apart from subtle color cues that help match up parentheses, brackets, and braces.

aoeui has no mail or news reader, IRC client, or artificial intelligence psychologist mode.

There is no X window system interface; that’s what xterm(1) and gnome-terminal(1) are for.


A text is a sequence of characters to be viewed or edited, such as a file. If not ASCII, the editor will automatically determine whether it is encoded in legal UTF-8 and do the right thing. The editor can also automatically detect DOS-style line endings. A view comprises all or part of a text. A text in the editor has at least one view, and possibly more.

A window is a rectangular portion of the display, and is always associated with a single view, a contiguous portion of whose text is rendered in the window. Not every view has a window.

Each view has a cursor and possibly a selection, which has the cursor at one end and the mark at the other. The view’s window, if any, always renders part of the text containing the view’s cursor.

The clip buffer is not visible in any window. It receives snippets of data that have been cut or copied out of texts, so that they may be moved or copied elsewhere. It also supplies the standard input to a background command launched with ^E (below). There is one clip buffer shared by all views.


aoeui uses colors to convey information without cluttering the display with status lines or borders between windows.

aoeui uses distinct background colors to distinguish tiled windows. The active window is always presented in the terminal’s default color scheme. Color is also used to highlight the current selection (in cyan) and folded regions (in red).

Needless tabs and spaces are marked in violet. These include any tabs or spaces before the end of a line, as well as any spaces followed by a tab or multiple spaces that could be replaced by a tab.

Bracketing characters are presented in alternating colors so that matching parentheses, brackets, and braces are colored identically.

A red cursor signifies a read-only text, whereas a green cursor indicates a dirty text (meaning one that needs saving, not one unfit for young persons).


Commands are denoted here by ^key to signify the use of Control, Alt, or a leading Escape key. They all mean the same thing.

Variant commands always begin with ^Space, or its synonym, ^@. A few commands take a numeric argument, which is specified by ^Space followed by a decimal or hexadecimal number, the latter using C language syntax (0xdeadbeef).

Many commands are sensitive to the presence or absence of a selection.



aborts the editor, leaving no original file modified since the last time ^K was used.


suspends the editor and returns the terminal to the shell that invoked it. Use the shell’s foreground command, probably fg, to resume editing.


saves all modified texts and terminates the editor.


The "backward and forward by unit" commands treat a numeric argument, if any, as a repeat count.


moves the cursor backward by characters.


moves the cursor forward by characters.


moves the cursor backward by words.


moves the cursor forward by words.


moves the cursor backward one sentence.


moves the cursor forward one sentence.


moves the cursor back to the beginning of the line. If already there, it moves back to the beginning of the previous line.


moves the cursor forward to the end of the line. If already there, it moves forward to the end of the next line.


moves the cursor back to the beginning of the paragraph. If already there, it moves back to the beginning of the previous paragraph.


moves the cursor forward to the end of the paragraph. If already there, it moves forward to the end of the next paragraph.


moves the window backward by screenfulls.


moves the window forward by screenfulls.


moves to the very beginning of the view.


moves to the very end of the view.


moves to the corresponding parenthesis, bracket, or brace, respecting nesting, if the cursor sits atop such a character. Otherwise, it moves to the nearest enclosing bracketing character.


recenters the window so that the line containing the cursor lies in the middle of its portion of the display.


causes the current window to occupy the entire display and recenters the window. With a numeric argument, however, it simply moves the cursor to the indicated line in the view, with 1 being the number of the first line.


(note that = is not a control character) sets a bookmark on the current selection or cursor position. A numeric argument may be used to manage multiple bookmarks.


(note that - is not a control character) returns to a previous set bookmark, possibly identified with a numeric argument.


(note that the single quote is not a control character) looks an identifier up the identifier in the TAGS file, which is automatically loaded into the editor if it is not already present, and if the identifier is found therein, the corresponding file name and line number are sought. The TAGS file should be generated with the ctags utility and its -x output format. If there is a selection, it is deleted from the view and its entire contents will constitute the identifier to be looked up; otherwise, the identifier that is immediately before or around the cursor is sought.


These commands are sensitive to the presence or absence of a current selection.


begins a new selection if non exists, setting its mark at the current cursor, which is then typically navigated to its intended other end. ^V in the presence of selection simply removes the mark.


without a selection causes the entire current line to be selected by placing the mark at the end of the line and the cursor at its beginning. It is the same as the command sequence ^C^V^G with no selection. With a selection present, ^Space^V exchanges its cursor with its mark.

Note that ^Space^V with a numeric argument unconditionally unsets the mark, which can be handy in a macro.

with no selection causes all of the contiguous white space characters surrounding the cursor to be selected, with the cursor at the beginning so that they can be easily replaced by retyping.


aoeui has infinite undo capabilities.


reverses the effects of the last command, apart from ^U itself, that modified the current text in any of its views.


reverses the effects of the most recent undo. After ^U, any other command that modifies the text will permanently commit the undo(s).


In the default mode, characters typed without a command indicator are inserted at the current cursor position. Further, if the cursor is at the beginning of a selection, the selection is first cut to the clip buffer, so that the new text replaces it.


(that’s Control-Shift-6, the caret character, on most keyboards, and ^6 will probably also work) inserts an untypeable control character into the text. The very next key to be pressed is either taken literally, if it is a control character, or converted to a control character if it is not, and inserted. (For example, you can press ^^ and then hit either Control-A or just a plain A, to get the character code 0x01 inserted.)


with a numeric argument, probably in hexadecimal, inserts the specified Unicode character into the text in UTF-8 format.


(or ^I) attempts to perform tab completion; if that fails, a TAB character is inserted. If there is a selection with the cursor at its end, the editor tries to find an unambiguous continuation based on path names and words in all the views. A continuation, if found, is appended to the selection, to facilitate opening a file with ^X. With no selection, but the cursor immediately after one or more identifier characters, the editor searches for an unambiguous continuation using the words in the views. A continuation, if found, is inserted as the new selection with the cursor at its end. No tab completion occurs when the cursor is at the beginning of a selection; in that case, the selection is cut and replaced with a single TAB character.


(or ^Space^I) will align the current line to the indentation of the previous one. With a numeric argument between 1 and 20, it will set the tab stop pitch.


(or ^Enter under some terminal emulators) inserts a new line into the text with automatic indentation.


(or ^Space^M) opens up a new line after the current one.


(or more properly, its synonym ^?), deletes the character immediately before the cursor.


with no selection deletes the character "under" the cursor. When a selection exists, ^D moves it into the clip buffer, discarding any previously clipped text.


with no selection will select surrounding white space, as described earlier. When a selection exists, ^Space^D moves it into the clip buffer, putting it before any old text if the cursor was at its beginning and appending it to the clip buffer if the cursor was at its end. The intent is for multiple ^Space^D commands to collect data together in the same order in which they are most likely to have been visited.


requires a selection, which is copied into the clip buffer and then unmarked.


is to ^F what ^Space^D is to ^D. It copies the selection to the clip buffer, putting it at the beginning or the end in the same way as ^Space^D (above).


with no selection will paste the current clip buffer’s contents. But in the presence of a selection it performs a more general function: the contents of the selection and the clip buffer are exchanged. With a numeric argument, ^B pastes or exchanges with a numbered register, which is an alternate clip buffer. (The main clip buffer is the same as register 0.) Besides being a means for preserving some text for longer periods of editing, the registers also serve as a means for extracting the text that matches a parenthesized subpattern in a regular expression search.



and its synonyms ^_ and ^A enter search mode. The variant command ^Space^/ searches for occurrences of POSIX regular expressions. Each non-command character that is typed thereafter will be appended to the current search target string and the selection is moved to the next occurrence thereof.

The case of alphabetic characters is not significant to the search.

Most command characters will automatically take the editor out of search mode before executing, and the most recently discovered occurrence of the search target string will be its selection.

A few commands have different meanings in search mode:

will remove the last character from the search target and move the selection back to its previous position.


is typically used to leave search mode with the cursor at the beginning of the latest hit, with the mark returned to where it was before the search (if anywhere).


(or ^_ or ^A ) with no characters in the search target string will cause the last search’s target string to be reused.


and ^T cause motion to the previous and next occurrences of the search target string, not single-character motion.


(and ^/, ^_, and ^A) simply leaves search mode with the last hit as the selection.



saves all modified texts back to their files.


saves just the current text.


with no selection inserts, as the new selection, the path name of the current text. With a selection containing a path name, possibly constructed with the assistance of tab completion (above), ^X will raise up a window containing a view into the indicated file, creating a new text to hold it if one does not already exist.


with a selection will rename the current text, so that it will be saved in another file.


finds an invisible view and associates it with the current window, making its current view invisible. Hitting ^W repeatedly will cycle through all of the views. If there was no invisible view, ^W creates a new scratch text, as does ^Space; below.


does the same thing. but will close the window’s current view, and also its text if it was the last view thereof.


splits the current window horizontally, raising up an invisible or new view in the lower half of the original window.


splits the current window vertically, raising up an invisible or new view in the right half of the original window.


moves to another window.


moves to another window, closing the old one.


(note that ; is not a control character) creates a new anonymous text.



commences the recording of your keystrokes as the current view’s local macro, which continues until the next ^O or another macro recording.


commences the recording of your keystrokes as a new global macro for a function key. Note that F1 and F11 are typically hijacked by window managers for their own purposes and probably will not be usable.


ends the recording of a macro, if one is in progress. Afterwards, ^O replays the view’s local macro, possibly with a repeat count as the argument. Note that a failed search in a macro will terminate its execution.


aoeui supports the "folding" of portions of text into what appear to be single characters, and the reverse "unfolding" operation. Further, to provide outline views of texts such as source code that are heavily indented, aoeui has an automatic nested folding capability.

with a selection will fold the selection. Otherwise, it will repeatedly fold indented regions of the text to provide an outline view. A numeric value, if any, specifies the number of leading spaces or equivalent tabs at which code lines will be folded. The default is 1, causing the folding of any line that isn’t left-justified.


with a selection will unfold the topmost foldings within it. Otherwise, if there is no numeric value, it will unfold the single folded region immediately beneath the cursor. With a numeric value, which is ignored, it will completely unfold the entire view.



with no selection will launch an interactive shell in a new scratch text. With a selection, however, ^E will execute the shell command in the selection with the contents of the clip buffer, if any, as its standard input, and collect its output asynchronously in the background to replace the selection. This allows many helpful UNIX text processing commands to be used directly. Some handy commands to know:


to include another entire file, or to receive writes to a named pipe


to create a named pipe so that commands in other windows may direct their output into a text running cat in the background.

cd path

to change the editor’s current working directory (a special case command that is not actually passed to a shell)


to search for lines containing a pattern


to rearrange lines alphabetically or numerically, possibly reversed


to discard duplicated lines


as in sed ’s/FROM/TO/g’ to perform unconditional search-and-replace with regular expressions


to convert lower to upper case with a-z A-Z and to remove DOS carriage returns with -d ’[\r]’


to reformat paragraphs of natural language text

indent -st -kr -i8 -nbbo

to reformat C language source code sensibly

column -t

to realign data nicely into columns

man | colcrt

to read a man page


to monitor additions to a file such as a log


to compile your code

aspell list | sort | uniq | column

to get a list of words that may be misspelled

^Space^E with no selection will terminate the output of any asynchronous child process that’s still running.



To select the rest of the line after the cursor, use ^V^C


It is often faster to retype a bungled word than to fix it, using ^V^N and then retyping.


Transposing multiple blocks of text is easy with ^B, which generalized the usual paste operation into an exchange of the clip buffer with the selection.


Incremental search and replacement can be done with a macro or by clipping the replacement text, and on search hits that are to be replaced, using ^B^F^/^/ to exchange the hit with the replacement text, copy it back to the clip buffer, and proceed to the next occurrence of the search pattern. But when the replacement text is short, it’s sometimes easiest to just overwrite the selection by hitting Enter to leave search mode and immediately retyping it, since the cursor will be placed at its beginning.


Reconfigure your keyboards so that the key to the left of A, which is probably labeled Caps Lock, is interpreted as a Control modifier instead.


The gnome-terminal(1) terminal emulator works well with aoeui if you configure the terminal’s scrollback limit to a relatively small value.


To move backward or forward by half a screenfull, use ^R or ^L and then ^Z.


Inevitable; please tell me about any that you find.



is used to name the program run by the ^E command.


and COLUMNS may be set to override aoeui’s automatic mechanisms for determining the size of the display surface.


when set to xterm will cause aoeui to try to set the title of the window to the name of the active view.



is overwritten with the original contents of file.


contains the temporary image of the edited file while aoeui is running, and may be useful in recovery if the editor is killed.


is read in by the ^Space’ command, if not already present, to supply the tags that are scanned. It should contain the output of ctags -x files.


holds any new "anonymous" texts created during editing sessions.


asdfg(1), ctags(1), regex(7)

Helpful commands to use with ^E: aspell(1), cat(1), colcrt(1), column(1), fmt(1), grep(1), indent(1), mkfifo(1), sed(1), sort(1), tailf(1), tr(1), uniq(1)


Peter Klausler <peter AT klausler DOT com> wrote aoeui.