xref: /csrg-svn/usr.bin/ex/READ_ME (revision 63050)

This is version 3 of the editor. It is too large to fit on a pdp-11
unless you have overlay code. (Such code is available for v7 unix on 2bsd.)

Version 2.13 corresponds to version 3 without the enhancements in 3.
There is no reason to use 2.13 unless you have a pdp-11 that does not have
overlay software, since 3 contains all the bug fixes and some new features.

Special installation notes for this version.
2) The include file varargs.h should be installed, as the printf here needs it.
3) The include file local/uparm.h should be installed, as ex_tune.h needs it.
   The contents of this include file can be modified if you wish to place
   the editor in a nonstandard location.

Conditional compilation flags:
	-DTRACE		for debugging (wont then fit on an 11)
	-DVFORK		for UCB Vax/Unix with the vfork system call.
	-DCHDIR		compile in undocumented old chdir (cd) command
	-DLISP		compile in lisp hacks
	-DUCVISUAL	compile in code to handle \ escapes for visual on
			upper case only terminals.  gross.
	-DCRYPT		-x option to edit encrypted files
	-DFLOCKFILE	compile in advisory file locking ala 4.[23X]

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Version 3.7  October 16, 1981

	It is now possible to split lines with substitute commands from vi,
	by using ^V<return> in the rhs.  This takes care of the last
	good reason for using ex command mode.

	Mode lines are now supported.  Put a line containing
		ex: xxx :
	in the first or last 5 lines of the file, where xxx is any ex
	command you want executed when that file is read in.  To make
	other programs happy, it should probably be inside a comment.
	You can use vi: as well as ex:.  (Note: no space allowed
	between the "ex" and ":".  The spaces around xxx are considered
	part of the command, and so are optional.)

	If there is a file .exrc in the current directory, it will be
	sourced when you enter vi, after your EXINIT or ~/.exrc.

	The changeable scrolling region of the vt100 is now used in
	place of insert line, resulting in much better performance.

	Vi uses the new AL, DL, LE, RI, DO, and UP (all upper case)
	termcap capabilities, which are parameterized versions of their
	lower case equivalents.  This will results in better performance
	on ANSI terminals, and especially on the Tektronix 4025 which
	has parameterized local motions but cannot cursor address.

	Vi uses backtabs again.  Now it knows how to handle backtabs on
	terminals that have tabs set at intervals other than 8, and it
	won't use backtabs if gtty indicates it can't use tabs.

	A bug causing <escape> <del> to core dump vi has been fixed.

	A bug causing writes to filters when editing encrypted files
	to write encrypted text has been fixed.

	A bug causing the message "substitution loop", when you enter a
	1,$s/xxx/yyy/g with lots of changes, has been fixed.

	A bug causing the current directory to be chmodded to 0 if you
	set nomesg after starting up the editor has been fixed.  Note
	that the nomesg option is intended for your EXINIT, since it only
	takes effect on entry to the editor.

	The eat newline glitch has been fixed so that vt100's and tab132's
	handle long lines correctly.

	Some internal changes have been made so that vi can run under UNIX
	on the Bell Labs 3B machine, the BBN C/70, and the IBM 370.

Version 3.6  October 30, 1980

	A kernel problem on the V7 pdp-11 overlay systems which causes
	bad EMT traps to happen randomly, core dumping the editor,
	has been programmed around by catching EMT traps.

	A bug which prevented using a screen larger than 48 lines has
	been fixed.

	A bug which allowed you to set window to a value larger than
	your screen size has been fixed.

	The screen size limit on non-VM/Unix systems has been increased
	to 66 lines or 5000 characters, to allow the Ann Arbor Ambassador
	terminal to be used.

	A bug which caused hangups to be ignored on USG systems has
	been fixed.

	A bug which caused maps with multiple changes on multiple lines
	to mess up has been fixed.

	If you get I/O errors, the file is considered "not edited" so
	that you don't accidently clobber the good file with a munged
	up buffer.

	An inefficiency in 3.5 which caused the editor to always call
	ttyname has been fixed.

	A bug which prevented the "source" command from working in an
	EXINIT or from visual has been fixed.

	A bug which caused readonly to be cleared when reading from
	a writable file with "r" has been fixed.

	The name "suspend" has been made an alias for "stop".

	The stop command now once again works correctly from command mode.

	On a dumb terminal at 1200 baud, "slowopen" is now the default.

	A bug in the shell script "makeoptions" which searched for a
	string that appeared earlier in a comment has been fixed.

	A bug that caused an infinite loop when you did ":s/\</&/g"
	has been fixed.

	A bug that caused & with no previous substitution to give
	"re internal error" has been fixed.

	A bug in the binary search algorithm for tags which sometimes
	prevented the last tag in the file from being found has been fixed.

	Error messages from expreserve no longer output a linefeed,
	messing up the screen.

	The message from expreserve telling you a buffer was saved when
	your phone was hung up has be amended to say the editor was
	terminated, since a kill can also produce that message.

	The "directory" option, which has been broken for over
	a year, has been fixed.

	The "r" command no longer invokes input mode macros.

	A bug which caused strangeness if you set wrapmargin to 1
	and typed a line containing a backslash in column 80 has
	been fixed.

	A bug which caused the "r<cr>" at the wrapmargin column
	to mess up has been fixed.

	On terminals with both scroll reverse and insert line,
	the least expensive of the two will be used to scroll up.
	This is usually scroll reverse, which is much less annoying
	than insert line on terminals such as the mime I and mime 2a.

	A bug which caused vi to estimate the cost of cursor motion
	without taking into account padding has been fixed.

	The failure of the editor to check counts on ^F and ^B commands
	has been fixed.

	The "remap" option failed completely if it was turned off.
	This has been fixed.

	A check of the wrong limit on a buffer for the right hand side
	of substitutions has been fixed.  Overflowing this buffer could
	produce a core dump.

	A bug causing the editor to go into insert mode if you typed
	return during an R command has been fixed.

	A bug preventing the + command from working when you edit a
	new file has been fixed by making it no longer an error to
	edit a new file (when you first enter the editor.)  Instead
	you are told it is a new file.

	If an error happens when you are writing out a file, such as
	an interrupt, you are warned that the file is incomplete.

Version 3.5 -- August 20, 1980

	The provisions for changing the window size with a numeric
	prefix argument to certain visual commands have been deleted.
	The correct way to change the window size is to use the z
	command, for example z5<cr> to change the window to 5 lines.

	The code to handle the -x (encryption) option has been made
	conditionally compiled, so that ex can run on an an 11/34 (!)
	with overlays.  Since this code calls getpass, stdio was
	being pulled in even without VMUNIX being defined.  The
	savings from not defining CRYPT are about 4K of text and 4.5K
	of bss.

	Bill Joy put in a buffering scheme under the VMUNIX flag so
	that up to 64K of file is edited in-core until you make enough
	changes to force a temp file sync.  This makes entry into the
	editor much faster, but also makes vi much bigger.

	The source to ex is now sccs'ed.

	An undocumented "feature" which caused the ^^ command to return
	to the previous tag, if in the current file, instead of the
	previous file, has been removed.

	A bug which prevented ex from compiling on systems with the new
	tty driver but no process control (such as Cory) was fixed.

Version 3.4 -- June 24, 1980

	The visual page motion commands ^F and ^B now treat any preceding
	counts as number of pages to move, instead of changes to the
	window size.  That is, 2^F moves forward 2 pages.

	A :vi <file> command from visual mode is now treated the same
	as a :edit <file> or :ex <file> command.  The meaning of the
	vi command from ex command mode is not affected.

	Provisions to handle the new process stopping features of the
	Berkeley TTY driver have been added.  A new command, "stop",
	takes you out of the editor cleanly and efficiently, returning
	you to the shell.  Resuming the editor puts you back in command
	or visual mode, as appropriate.  If autowrite is set and there
	are outstanding changes, a write is done first unless you say
	"stop!".  From visual mode, the command ^Z is the same as :stop.
	Note that if you have an arrow key that sends ^Z the stop function
	will take priority over the arrow function.  If you have your
	"susp" character set to something besides ^Z, that key will be
	honored as well.

	A read only mode now lets you guarantee you won't clobber your
	file by accident.  You can set the on/off option "readonly" (ro)
	and writes will fail unless you use an ! after the write.
	Commands such as x, ZZ, and autowrite, and in general anything
	that writes is affected.  This option is turned on if you invoke
	ex with the -R flag.  A new link called "view" has been  created.
	View is just like vi but it sets readonly.

	The encryption code from the v7 editor is now part of ex.
	You invoke ex with the -x option and it will ask for a key,
	as ed.  The ed "x" command (to enter encryption mode from
	within the editor) is not available.

	The editor now adopts the convention that a null string in the
	environment is the same as not being set.  This applies to
	TERM, TERMCAP, and EXINIT.

	A word abbreviation mode is now available.  You can define
	abbreviations with the abbreviate command
		:abbr foo find outer otter
	which maps "foo" to "find outer otter".  Abbreviations can be
	turned off with the "unabbreviate" command.  The syntax of these
	commands is identical to the map and unmap commands, except
	that the ! forms do not exist.  Abbreviations are considered
	when in visual input mode only, and only affect whole words
	typed in, using the conservative definition.  (Thus "foobar"
	will not be mapped as it would using map!)
	Abbreviate and unabbreviate can be abbreviated to "ab" and
	"una", respectively.

	The editor now supports certain terminals that use strings other
	then \r and \n for return and linefeed by implementing the cr
	and nl termcap options.  (Thanks to UCLA for these enhancements).

	The termcap attribute ns is now checked for, and ex refuses to
	go into visual mode on such a terminal unless it has sf.

	Terminals that can cursor address but cannot go up a line
	now work in visual.

	If you change your start and stop characters to something other
	than the default ^S and ^Q, vi now turns them off.  This causes
	people who change them to escape not to lose so badly.
	The quit character is once again turned off so that datamedias
	which send ^\ for the right arrow key work.

	The ~ command now repeats correctly with ".".

	If you type in an unmatched ) or } in showmatch mode, the editor
	will now beep to warn you about your mistake.  The ) or } is
	still accepted.

	The way macros are undone has been improved considerably.
	The number of changes inside the macro is counted, and just
	before the second change the state before the macro is recreated
	internally and saved to allow the macro to be undoable as a unit.
	Hence, if the macro makes only one change the particular change is
	undone (which will probably not redraw the screen).  If no changes
	are made (for example, the arrow keys) the previous thing that could
	be undone is not clobbered.

	The undomacro option has been deleted since it is no longer needed.

	Editor scripts can now contain comments.  Begin the comments with "
	(double quote).  Comments can be on their own line or come at the
	end of command lines.  The comment continues to the end of the line.

	The 3rd version of the USG tty driver is now supported, making it
	possible on USG systems to interrupt redrawing the screen and to
	not flush output when interruptable commands take place.

	The rewind command has been added to the list of commands that
	the autowrite option knows about.

	The wrapmargin option is now usable.  The way it works has been
	completely revamped.  Now if you go past the margin (even in the
	middle of a word) the entire word is erased and rewritten on the
	next line.  This changes the semantics of the number given to
	wrapmargin.  0 still means off.  Any other number is still a
	distance from the right edge of the screen, but this location
	is now the right edge of the area where wraps can take place,
	instead of the left edge.  Wrapmargin now behaves much like
	fill/nojustify mode in nroff.

	A bug on the USG system where hanging up the phone causes more
	than one SIGHUP to be sent has been compensated for.

	A bug which caused the :sh command not to send the vs and ti
	sequences when you returned has been fixed.

	A bug which caused a file that bombed out in the middle of
	an edit command to be considered modified has been fixed.

	A bug which caused the screen to be wrong after undoing a
	:move command has been fixed.

	A bug which messed up the buffer and the screen after
	undoing a :join command has been fixed.

	The source file ex_io.c has been split into ex_io.c and
	ex_unix.c to avoid a problem where many C compilers overflowed
	the symbol table.

	A bug which prevented turning off your prompt in your .exrc
	has been fixed.

	Some of the code internal to the editor has been rearranged
	and some comments added.

	The bug fix to the USG tty driver to output a null character
	as padding at 1200 baud has been improved to output a DEL
	at 1200 baud or above.

	Terminals with small screens (less than 20 columns or less
	than 5 lines) should now work.

	A bug which prevented you from entering the character DEL
	into the buffer if you changed your interrupt character to
	something else besides DEL has been fixed.

	A bug which caused the current line to be clobbered when
	you did a /, ?, or : command which mapped an input macro
	successfully has been fixed.

	If you map o to O and O to o and have remap set, the editor
	now catches the infinite loop.

	A put command after a macro now beeps instead of putting
	a copy of the whole buffer.  (Note that the arrow keys
	on terminals are considered macros.)

	A bug which caused things like d) and d} to miss the last
	character when they should have deleted to the end of the
	buffer has been fixed.

	A bug which caused the last character to be lost when you
	read in a file with no newline at the end of the last line
	has been fixed.

	A bug that caused garbage to be in the buffer if the temp file
	overflowed has been fixed.  (This only affected non-VMUNIX systems
	since the temp file cannot overflow on VMUNIX.)

	When a macro or global is undone, you no longer get picked up and
	dropped on line 1.

	The character | can now be escaped with \| in file names.

	A bug which prevented the confirm option to a substitution that
	was inside a source command has been fixed.

	A bug which caused the editor to not work if the tab stop size
	did not divide the screen width has been fixed.

	A bug on HP terminals that caused the screen to be messed up if
	you scrolled up something that began the same way as the echo line
	has been fixed.

	A macro bug which sometimes caused the next character after an
	escape to be ignored on an HP terminal has been fixed.

	A bug which caused unmap of strings with length 2 to fail has been
	fixed.

	A bug which left vi confused if you invoked a macro containing a
	quit to command mode and then did an undo has been fixed.

	An old ed bug which caused globals to fail when they did a substitute
	on the next line has been fixed.

	The % operator will now find matching square brackets the same way
	it does parentheses and braces.  It will not display them in
	showmatch mode, however, and will not use a ] to match all ('s.

	Code has been added to handle the Beehive Superbee terminal,
	using f1 for escape and f2 for control C.

	The default value of the option shell is now taken from the
	environment variable SHELL, if present.

Version 3.3 -- February 2, 1980

	The default window sizes have been changed.  At 300 baud the
	window is now 8 lines (was 1/2 the screen size).  At 1200 baud
	the window is now 16 lines (was 2/3 the screen size, which was
	usually also 16 for a typical 24 line CRT).  At 9600 baud the
	window is still the full screen size.  Any baud rate less than
	1200 behaves like 300, any over 1200 like 9600.

	A new command mode command "x" (for "xit") has been added.  This
	is the same as wq but will not bother to write if there have been
	no changes to the file.  The command letter was chosen for
	convenience and compatibilty with hed.

	The command "ZZ" from vi is the same as ":x<cr>".  This is
	the recommended way to leave the editor.  Z must be typed twice
	since this is two easy to type by accident and has such severe
	effects if unintentional.

	The options w300, w1200, and w9600 can be set.  They are synonyms
	for "window", but only apply at 300, 1200, or 9600 baud, resp.
	Thus you can specify you want a 12 line window at 300 baud and
	a 23 line window at 1200 baud with
		:set w300=12 w1200=23

	It is now possible to say
		:set window=5
	and get the effect the next time the screen is redrawn from scratch.
	(^L and Hit return to continue don't start from scratch.)
	This is sort of pointless, since both
		5:<cr>
	and
		z5<cr>
	do the same thing with better results.

	The editor no longer uses nondestructive space, except when in
	insert mode.  It instead prints the character it would be
	moving over.  This is a real win on terminals that use an
	escape sequence to nd space.

	It is now possible from visual to string several search expressions
	together separated by semicolons the same as command mode.  For
	example, you can say
		/foo/;/bar
	from visual and it will move to the first "bar" after the next "foo".
	This also works within one line.

	The option "mapinput" is dead.  It has been replaced by a much
	more powerful mechanism: :map! (e.g. put an ! after the map).
	Map and unmap commands with ! apply only to input, others apply
	only to command mode.

	The new option "timeout" (default on) causes macros to time out
	after one second.  Turn it off and they will wait forever.

	By using map! and setting notimeout, it is possible to get the
	effect of emacs abbreviation mode.  Sanity checking is turned off
	for map when ! is present.  This is a crude facility and does not
	take into account things like the abbreviation being part of a longer
	word.  It also does not echo until it is satisfied.

	The new option "remap" (default on) causes the editor to attempt
	to map the result of a macro mapping again until the mapping fails.
	This makes it possible, say, to map q to # and #1 to something else
	and get q1 mapped to something else.  Turning it off makes it possible
	to map ^L to l and map ^R to ^L without having ^R map to l.

	The new option "undomacro" (default on) makes it possible to undo
	macros as a unit.  Leaving it off causes macros not to be treated
	specially.  Macros with zero or one change work better with noum,
	with two or more changes better with um.  This option may go away
	if it becomes unnecessary.

	The new (string) valued option "tags" allows you to specify a list
	of tag files, similar to the "path" variable of csh.  The files
	are separated by spaces (which are entered preceded by a backslash)
	and are searched left to right.  The default value is
	"tags /usr/lib/tags", which has the same effect as before.
	It is recommended that "tags" always be the first entry.
	On Ernie, /usr/lib/tags contains entries for the system defined
	library procedures from section 3 of the manual.

	^R is now the same as ^L on terminals where the right arrow key
	sends ^L (The tvi and the adm 31).

	Looking for a tag now uses binary search.

	The "q" command from visual no longer works at all.  You must
	use "Q" to get to ex command mode.

	A minor incompatibility with the v7 ed has been fixed.  Previously,
	to do a global substitute with an escaped newline in the rhs, you
	had to put two \'s in ex and one in ed.  Ex now accepts the single
	form as well as the double form.  For example, instead of
		g/foo/s//foo\\
		bar/g
	(which still works), you can now type, as in ed,
		g/foo/s//foo\
		bar/g
	This means that the following ex command, which used to "work":
		g/foo/s//foo bar\
		.+1,/mumble/d
	won't work anymore unless you put the trailing / on the substitution.
	This usage is pretty obscure anyway.

	Several bugs relating to undoing macros have been fixed.

	A bug which caused the command "g/pattern" to print an error
	message if "pattern" occurred on the last line has been fixed.

	If you reply ":" to "Hit return to continue", you will again be
	asked "Hit return to continue" after the next command finishes.

	Limits have been raised so that an Ann Arbor terminal can be used,
	and long tags can now be accomodated.

	The maximum length of a string valued option has been raised from
	32 to 64, for the benefit of the "tags" option.

	It is now possible to search for an escape or delete using f, F, t,
	T, ;, and ,.  These characters must be quoted with ^V.

	The option "ttytype" is now in correct alphabetical order.

	A bug that caused HP terminals to mess up in insert mode when inserting
	before a tab which follows 7 or fewer characters at the beginning of a
	line (such as a tags file) has been fixed.

	It is now possible to include control D in your EXINIT or .exrc.

	A bug which caused the screen to mess up when a glob (such as xx*)
	doesn't match anything has been fixed.

	The editor now checks for extra junk after a /r.e./ from visual
	(other than the allowed z command) and beeps if any is found.
	Previously it was just ignored.

	A bug that caused j and k (up and down) to behave strangely after
	an insertion has been fixed.

	A bug which causes term to be displayed incorrectly and which
	caused a crash when changing terminal type when there happened
	to be several |'s and a long string in genbuf has been fixed.
	This bug was introduced in ex 2.9.

	The patch for echo lines longer than 80 characters has been
	repaired to do "Hit return to continue" after such lines and
	print the entire output.

	A bug that caused a messed up screen after a :sh command from
	open mode has been fixed.

	A bug which caused a tag request for a nonexistant tag to leave
	the editor in nomagic mode has been fixed.

	A bug which caused strange behavior if there is no default file
	name when an autowrite save is attempted has been fixed.

	A bug which caused the cursor to go to the wrong position when
	^^D or 0^D is entered from column 2 in autoindent mode on terminals
	that can backspace has been fixed.

Version 3.2 -- January 4, 1980

	A bug that caused nomagic to be set if an error happened within
	a tag command has been fixed.

	A bug that caused put commands to beep after a macro containing
	an error has been fixed.

	The mapinput option has been placed in alphabetical order.

	A bug that caused undo to undo more than one macro invocation
	on the same line has been fixed.

	On non VM/UNIX systems, the screen size has been increased to
	allow a 40 X 80 Ann Arbor to be used.

Version 3.2 -- December 28, 1980

	Several limits have been increased for VM/UNIX.  Longer lines,
	more characters of file names, longer regular expressions, etc.
	Huge files can now be edited directly.  Larger terminals (up to
	66 lines) can be used.

	An internal change has been made for VM/UNIX that causes error
	messages to be stored directly instead of in a disk file.
	This should cause faster response to errors.

Version 3.1.1 -- December 13, 1979

	A bug that caused nested macros not to be undoable has been fixed.

	A bug that caused pounding on the escape key on terminals with
	arrow keys that send escape sequences to cause undo to screw up
	has been fixed.

	It is now acknowledged that macros cannot contain the put command.
	This is due to the implementation of put - previously a put inside
	a macro dumped a copy of the buffer instead of the desired text and
	left the editor in a very strange state.  Now such a put just beeps.

Version 3.1 -- November 1, 1979

	Versions from 3.1 up are too large to fit on pdp-11's.
	(Special overlay software is expected to be available soon
	for v7 pdp-11 Unix that will make it fit.) Version 2.9
	is 3.1 with only the bug fixes and very few of the enhancements.
	2.9 will fit on a pdp-11. Version 2.10 will come out and may
	correspond to 3.2. (It turned out to correspond to 3.3)

	For compatibility with ed:  's<newline>' may be used as a
	command and means '&'.  If you set the option "edcompatible"
	(abbr "ed") the presense or abscence of g and c suffices is
	remembered and can be toggled by repeating the suffices.  The
	suffix "r" makes the substitution into "~" instead of "&".

	A new command line option -w<n> sets the value of window before
	starting ex. Hence: 'vi -w5 file' makes a quick change to a file
	easier at 300 baud.

	Arrow keys on terminals that send more than 1 character now
	work.  Home up keys are supported as are the four directions.
	Ex no longer looks at the ma= entry in termcap, but uses the
	ku, kd, kl, kr, and kh entries.  (Note that the HP 2621 will
	turn on function key labels, and even then you have to hold
	shift down.  To avoid turning on the labels, and to give up the
	function keys, use terminal type 2621nl instead of 2621.)

	A parameterless macro facility is included from visual. Briefly,
	there are two flavors of macros:
		a) Put the macro body in a buffer register, say x. Then
		   type @x to invoke it. @ may be followed by another @
		   to repeat the last macro.
		   This allows macros up to 512 chars.
		b) Use the map command from command mode (typically in the
		   .exrc file) as follows:
			map lhs rhs
		   where lhs will be mapped to rhs.
		   There are restrictions: lhs's should be 1-keystroke
		   (either 1 char or 1 function key) since they must be
		   entered within 1 second. lhs no longer than 10 chars,
		   rhs no longer than 100. To get " ", "\t", "|", or "\n"
		   into lhs or rhs, escape them with ctrl V. (It may be
		   necessary to escape the ctrl V with ctrl V if the map
		   command is given from visual mode.)
	For 1 shot macros it is best to put the macro in a buffer register
	and map a key to '@r', since this will allow the macro to be edited.

	Macros can be deleted with
		unmap lhs

	The boolean option "mapinput" (mi) will, if on, cause macros to
	be mapped in input mode as well as command mode (in visual only).
	For example, you can define ctrl T to be four spaces with
		:map ^V^T_^V^V____
		:set mi
	where underlines represent spaces and the ctrl V's are necessary
	to get ctrl chars and spaces past various levels, and make ^T be
	a software tab that even works in the middle of a line.

	If the lhs of a macro is "#0" through "#9", this maps the particular
	function key instead of the 2 char # sequence, if the terminal has
	function keys. This only works if termcap has function key entries
	for the particular terminal. For terminals without function keys,
	the sequence #x means function key x, as typed. As a special case,
	on terminals without function keys, the #x sequence need not be
	typed within one second. The character # can be changed by using
	a macro in the usual way:
		map ^V^I #
	to use tab, for example. (This won't affect the map command, which
	still uses #, but just the invocation from visual mode.)
	The undo command will undo an entire macro call as a unit.

	New commands in visual: ^Y and ^E. These glitch the screen up
	and down 1 line, respectively. They can be given counts, controlling
	the number of lines the screen is glitched. They differ from ^U
	and ^D in that the cursor stays over the same line in the buffer
	it was over before rather than staying in the same place on the
	screen. (^Y on a dumb terminal with a full screen will redraw the
	screen moving the cursor up a few lines.) If you're looking for
	mnemonic value in the names, try this: Y is right next to U and
	E is right next to D.

	More new commands in visual: '&' is a synonym for ':&<cr>'.
	'~' changes the case of the letter under the cursor and moves
	to the next character.

	Ex looks in your environment for EXINIT. If it finds it, that
	is used instead of looking for your .exrc. This should make
	entry into ex faster, along with the termlib feature of looking
	for a termcap entry in TERMCAP.

Version 2.13 -- September 23, 1980

	The provisions for changing the window size with a numeric
	prefix argument to certain visual commands have been deleted.
	The correct way to change the window size is to use the z
	command, for example z5<cr> to change the window to 5 lines.

	An undocumented "feature" which caused the ^^ command to return
	to the previous tag, if in the current file, instead of the
	previous file, has been removed.

Version 2.12 -- July 23, 1980

	A change was made to the sys_errlist array in ex_subr.c so that
	Berkeley V7 quotas will produce the right error message.

	A couple of minor bug fixes were made to get the editor to
	compile on version 6.  The option to use 1K BUFSIZ has been
	deleted, since it is no longer used on our 1K system.

Version 2.11 -- June 24, 1980

	The visual page motion commands ^F and ^B now treat any preceding
	counts as number of pages to move, instead of changes to the
	window size.  That is, 2^F moves forward 2 pages.

	A :vi <file> command from visual mode is now treated the same
	as a :edit <file> or :ex <file> command.  The meaning of the
	vi command from ex command mode is not affected.

	A read only mode now lets you guarantee you won't clobber your
	file by accident.  You can set the on/off option "readonly" (ro)
	and writes will fail unless you use an ! after the write.
	Commands such as x, ZZ, and autowrite, and in general anything
	that writes is affected.  This option is turned on if you invoke
	ex with the -R flag.  A new link called "view" has been  created.
	View is just like vi but it sets readonly.

	The editor now supports certain terminals that use strings other
	then \r and \n for return and linefeed by implementing the cr
	and nl termcap options.  (Thanks to UCLA for these enhancements).

	The termcap attribute ns is now checked for, and ex refuses to
	go into visual mode on such a terminal unless it has sf.

	If you change your start and stop characters to something other
	than the default ^S and ^Q, vi now turns them off.  This causes
	people who change them to escape not to lose so badly.
	The quit character is once again turned off so that datamedias
	which send ^\ for the right arrow key work.

	If you type in an unmatched ) or } in showmatch mode, the editor
	will now beep to warn you about your mistake.  The ) or } is
	still accepted.

	Editor scripts can now contain comments.  Begin the comments with "
	(double quote).  Comments can be on their own line or come at the
	end of command lines.  The comment continues to the end of the line.

	The 3rd version of the USG tty driver is now supported, making it
	possible on USG systems to interrupt redrawing the screen and to
	not flush output when interruptable commands take place.

	The rewind command has been added to the list of commands that
	the autowrite option knows about.

	A bug on the USG system where hanging up the phone causes more
	than one SIGHUP to be sent has been compensated for.

	A bug which caused a file that bombed out in the middle of
	an edit command to be considered modified has been fixed.

	The source file ex_io.c has been split into ex_io.c and
	ex_unix.c to avoid a problem where many C compilers overflowed
	the symbol table.

	A bug which prevented turning off your prompt in your .exrc
	has been fixed.

	Some of the code internal to the editor has been rearranged
	and some comments added.

	The bug fix to the USG tty driver to output a null character
	as padding at 1200 baud has been improved to output a DEL
	at 1200 baud or above.

	Terminals with small screens (less than 20 columns or less
	than 5 lines) should now work.

	A bug which prevented you from entering the character DEL
	into the buffer if you changed your interrupt character to
	something else besides DEL has been fixed.

	A bug which caused things like d) and d} to miss the last
	character when they should have deleted to the end of the
	buffer has been fixed.

	A bug which caused the last character to be lost when you
	read in a file with no newline at the end of the last line
	has been fixed.

	A bug that caused garbage to be in the buffer if the temp file
	overflowed has been fixed.

	The character | can now be escaped with \| in file names.

	A bug which caused the editor to not work if the tab stop size
	did not divide the screen width has been fixed.

	A bug on HP terminals that caused the screen to be messed up if
	you scrolled up something that began the same way as the echo line
	has been fixed.

	An old ed bug which caused globals to fail when they did a substitute
	on the next line has been fixed.

	The % operator will now find matching square brackets the same way
	it does parentheses and braces.  It will not display them in
	showmatch mode, however, and will not use a ] to match all ('s.

	Ex looks in your environment for EXINIT. If it finds it, that
	is used instead of looking for your .exrc. This should make
	entry into ex faster, along with the termlib feature of looking
	for a termcap entry in TERMCAP.

	Internally, it is possible to turn off about a dozen different
	options when compiling the editor to make it fit in 64K.
	See the makefile for a list of options.

Version 2.10 -- February 2, 1980 (Corresponds to 3.3)

	The default window sizes have been changed.  At 300 baud the
	window is now 8 lines (was 1/2 the screen size).  At 1200 baud
	the window is now 16 lines (was 2/3 the screen size, which was
	usually also 16 for a typical 24 line CRT).  At 9600 baud the
	window is still the full screen size.  Any baud rate less than
	1200 behaves like 300, any over 1200 like 9600.

	A new command mode command "x" (for "xit") has been added.  This
	is the same as wq but will not bother to write if there have been
	no changes to the file.  The command letter was chosen for
	convenience and compatibilty with hed.

	The command "ZZ" from vi is the same as ":x<cr>".  This is
	the recommended way to leave the editor.  Z must be typed twice
	since this is two easy to type by accident and has such severe
	effects if unintentional.

	The options w300, w1200, and w9600 can be set.  They are synonyms
	for "window", but only apply at 300, 1200, or 9600 baud, resp.
	Thus you can specify you want a 12 line window at 300 baud and
	a 23 line window at 1200 baud with
		:set w300=12 w1200=23

	The "q" command from visual no longer works at all.  You must
	use "Q" to get to ex command mode.

	The editor no longer uses nondestructive space, except when in
	insert mode.  It instead prints the character it would be
	moving over.  This is a real win on terminals that use an
	escape sequence to nd space.

	A minor incompatibility with the v7 ed has been fixed.  Previously,
	to do a global substitute with an escaped newline in the rhs, you
	had to put two \'s in ex and one in ed.  Ex now accepts the single
	form as well as the double form.  For example, instead of
		g/foo/s//foo\\
		bar/g
	(which still works), you can now type, as in ed,
		g/foo/s//foo\
		bar/g
	This means that the following ex command, which used to "work":
		g/foo/s//foo bar\
		.+1,/mumble/d
	won't work anymore unless you put the trailing / on the substitution.
	This usage is pretty obscure anyway.

	A bug which caused the command "g/pattern" to print an error
	message if "pattern" occurred on the last line has been fixed.

	Limits have been raised so that an Ann Arbor terminal can be used,
	and long tags can now be accomodated.

	A bug that caused HP terminals to mess up in insert mode when inserting
	before a tab which follows 7 or fewer characters at the beginning of a
	line (such as a tags file) has been fixed.

	A bug which causes term to be displayed incorrectly and which
	caused a crash when changing terminal type when there happened
	to be several |'s and a long string in genbuf has been fixed.
	This bug was introduced in ex 2.9.

	The patch for echo lines longer than 80 characters has been
	repaired to do "Hit return to continue" after such lines and
	print the entire output.

	A bug that caused a messed up screen after a :sh command from
	open mode has been fixed.

	A bug which caused a tag request for a nonexistant tag to leave
	the editor in nomagic mode has been fixed.

	A bug which caused strange behavior if there is no default file
	name when an autowrite save is attempted has been fixed.

	A bug which caused the cursor to go to the wrong position when
	^^D or 0^D is entered from column 2 in autoindent mode on terminals
	that can backspace has been fixed.

	In order to get 2.10 to fit on a v7 pdp-11, the following features
	have been deleted:
		The MASTERTAGS feature (undocumented use of /usr/lib/tags
		as an alternate tag file)
		Checking that a file being read in is an ascii file.
		Turning off ^Q/^S on a v7 system.

Version 2.9 -- November 1, 1979

	The meanings of semicolon and newline, broken in 2.8, have been fixed.
	Newline with two arguments still prints the range, unless a semicolon
	was present, in which case only the last line is printed. Semicolon
	otherwise behaves as in ed (and ex 2.7).

	For compatibility with ed: '%' is an abbreviation for '1,$'.
	The default starting line for 'z' is '.+1' instead of '.'.
	If 'z' is followed by a number, this number is remembered
	(by setting the scroll option).

	The + options to the command line invocation and to the edit
	command now also work for the next command. In addition, the
	text after the + is no longer limited to a line number or
	/ or ? search string, but can be any single command. (It cannot
	contain spaces except on command line invocation, and then must
	be quoted to make the shell happy.)  The only special case is
	where + is used by itself - this is the same as +$.

	The way window sizes and scrolling commands are based on the options
	window and scroll has been rearranged. All command mode scrolling
	commands (z and ctrl D) are based on scroll: ^D moves scroll lines,
	z moves scroll*2 lines. Everything in visual (^D, ^U, ^F, ^B, z,
	window sizes in general) are based on the window option. The
	defaults are arranged so that everything seems as before, but
	on hardcopy terminals at 300 baud the default for scroll is
	11 instead of 6.

	Whether ex prompts for commands now depends on the setting of the
	prompt variable, so inside script you can say 'set prompt' and
	get ex to prompt.

	Tags are now searched for in nomagic mode instead of the funny
	mode where magic characters were impossible to get.

	Paragraphs and sections with one letter names (such as those
	used by PWB/MM) now work - use a space (escaped by a backslash)
	for the second letter. Default paragraphs and sections are included
	for both MM and MS. (Thanks to adb for this)

	A bug involving 16 bit arithmetic on a vax for the yank command
	has been fixed.

	The text of the mailed message from expreserve has been improved
	slightly.

	The editor now always turns off the XTABS stty bit when in visual
	mode, making terminals that do special things with ^I work.

	The editor now knows about terminals with destructive tabs, like
	the teleray 1061, having the xt option.

	A bug that caused going past column 80 on terminals with insert line
	but not insert char (like the mime, h1500, or i100) to mess up the
	screen has been fixed.

	A bug on 2621's that causes lines longer than 80 chars long with
	embedded tabs to mess up when a tab was inserted has been fixed.

	A bug that caused the wrong line to suddenly appear under very
	rare circumstances involving small window sizes and long lines
	where a search left the cursor on the top line of the screen
	has been fixed.

	The bug that caused inverse video to sometimes be scrolled up
	into the file from an error message has been fixed.

	The join command has been fixed, so that '3,3j' no longer joins
	lines 3 and 4. ('3j' still does.) Thus, '/a/;/b/-j' works right
	even if b is found on the line after a.

	ex -v now finds your .exrc. In related changes, the default in
	vi is now magic and nobeautify.

	If your buffer is empty, ex won't refuse to do an edit, quit,
	or tag command because you haven't done a write.

	A bug causing visual undo not to work after '1,$!cat' has been
	fixed.

	Ex now decides for itself whether to use CBREAK or TIOCSETN
	by whether they are defined in <sgtty.h>. This eliminates much
	of the #ifdef USG or V6 lines. One USG line remains due to a bug
	in the USG tty driver at 1200 baud.
	Note that this will mess up if you use libretro because <sgtty.h>
	has CBREAK and TIOCSETN defined. Take these out of sgtty.h to fix this.

	Termcap options TI and TE have been added.  These strings are
	respectively output at the beginning and end of the editing session.

	Values for the set command may now include `\ ' for space and
	control characters.

	Changes have been made to /etc/termcap (several new fields have
	been added) and to termlib (it now looks for TERMCAP in the environment
	and treats it as a termcap entry if the name of the terminal mentioned
	is the same as TERM and the entry doesn't start with a slash.
	If it starts with a slash it is treated as a filename, as before.
	Termcap also checks the 512 byte entry limit and skips lines beginning
	with # as comments. It is possible to define one terminal as being
	similar to another one with a few differences without making two
	copies of the description.) New termcap fields:
		ti	terminal initialization string. This should be sent
			out at the beginning of any program that addresses
			the cursor.
		te	Like te but at end of the program.
			(Thanks to adb for these two fields)
		us	Start underlining.
		ue	End underlining.
		uc	Underline one character & move over it.
		hc	(bool) terminal is hardcopy
		ns	(bool) terminal doesn't scroll (tektronix)
		ff	(bool) hardcopy knows ^L means formfeed.
		pt	(bool) hardware tabs, maybe set by is
		xt	(bool) destructive tabs (teleray 1061)
		ku	sequence sent by keypad "up" arrow
		kd	"down" arrow
		kl	"left" arrow
		kr	"right" arrow
		kh	"home" arrow
		ks	sequence to make keypad send these codes
		ke	sequence to make keypad not send these codes.
		k0-k9	sequences sent by up to 10 "other" keys
		l0-l9	labels on k0-k9. If omitted, default = "f0" - "f9".
		ko	additional keys on keypad, in terms of their
			termcap entry. For example, if "home down" and "clear"
			are present and send the same codes as ll and cl, use
				:ko=cl,ll:
		tc	This entry is a list of differences from the named
			entry. THIS MUST BE THE LAST FIELD. Example: hp2621
			with no ks or ke (e.g. null string):
				hn|hp2621nl:ks@:ke@:tc=hp2621:
			The @ cancels the string even if it is defined later.

Version 2.8 -- July 18, 1979

	It is now possible to backspace over the first character (:, /, or ?)
	on the echo line from visual. The effect is as though delete were hit
	except the bell isn't rung.

	The trailing slash in global commands is now optional.
	g/pat	means	g/pat/p
	(This change, as well as the corresponding changes to the substitute
	command and r.e. address are also in the latest version of ed.)

	The j, k, and l keys now move the cursor down, up, and right,
	respectively, in visual mode, as they used to do (and still do on
	3a's). This is to avoid the creeping of these keys into the map
	descriptions of terminals and to compensate for the lack of arrow
	keys on terminals like HP's.

	Two arguments given to a newline command now print the range of
	lines instead of just the last line (as though 'p' were appended).
	To make forms like /foo/;/bar/	still work, the ; operator sets
	the dot as before but then forgets everything to the left of the ;.

	The + option invoked from the shell or the edit command has
	two new forms:	+/pat	and 	+?pat
	These cause the initial line to be chosen by a search for the
	pattern pat. Note that if any special characters are in the
	argument (such as ^, $, and even ?) it must be quoted.

	Two new options are added: autowrite (aw) and hardtabs (ht).
	Autowrite is a toggle, off by default. When on, if you have
	unsaved changes before a context switching command, a write
	is done automatically. The commands that may write are !,
	next, and tag. Note that there is an equivalent way to do the
	command with autowrite set without the write in each case:
	shell, tag!, and edit do not write.

	Hardtabs is a numeric option,, set to 8 by default.
	Changing this to, say, 4, tells ex that either your system
	expands tabs to every 4 spaces, or your terminal has hardware
	tabs set every 4 spaces.

	A bug that caused strange behaviour when an echo line contained
	more than 79 characters (from a long : command or one or more long
	filenames) has been patched by not printing any such characters
	past column 79.

	Handling of systems with nonstandard locations of files (where
	the maintainer of ex is not a superuser and cannot create files
	with names like /usr/lib/ex2.0strings or /etc/termcap) has been
	improved. If the file can't be found as is, it is tried in the
	current directory. If that fails, ex tries to run without it.
	(Previously it bombed immediately if the error message file wasn't
	in /usr/lib.)

	Shell commands containing ! or % characters are no longer echoed
	when in hush mode (as in 'ex -' from a shell file.)

Version 2.7 -- June 10, 1979

	An inefficiency introduced in version 2.3, which increased the
	amount of time spent preparing output by approximately 30 percent
	has been corrected.

	A bug which caused ``wrapmargin'' to work as though all hardcopy
	terminals were 160 columns wide has been corrected.

	A bug which caused the display to become confused after the display
	of a long line at the bottom of the screen was suppressed (being
	replaced temporarily by an @) has been fixed.  Previously, under
	some circumstances (e.g. after a put created the situation), scrolling
	up of the following text would cause the display of this long
	line to be skipped, so that the @ line would remain and the line
	itself would not be displayed.

Version 2.6 -- June 2, 1979

	A bug which prevented the first field separator in a tags file
	from beginning with a blank has been fixed; if the separator
	was a blank previously, the tag would not be found in the tags file.

	A bug which caused the display to be messed up after a ``:''
	escape which created long lines has been fixed.  Previously
	a substitute command which changed the last few lines on the screen
	to be very long would leave the screen messed up.

	A bug in display after 2 successive ``undo'' commands has been fixed.
	Previously if you opened new lines on the display, and then did
	2 successive undo commands, the display would be messed up after the
	second undo if your terminal had insert/delete line.

	A bug on intelligent terminals which caused unnecessary delete
	character commands to be sent has been fixed.  This occurred when
	you did not have ``autoindent'' set, and opened a new line
	below an existing line with tabs.

	The change operations in open mode on hardcopy terminals has been
	fixed.  Previously there were several bugs in cursor placement
	when the change extended to just before a tab character.

	Several bugs in the handling of tabs in insert mode on intelligent
	terminals have been fixed.  Previously, tabs would often expand
	incorrectly, leaving the wrong amount of white space, when an
	insert occurred just before a tab.

	A bug has been fixed which caused the editor to skip processing
	of the ``.exrc'' file when the terminal type set in the
	environment was unknown.  The editor now processes ``.exrc'' in
	this case.

	[[A number of formatting changes have been made to the editor code
	to eliminate unreasonably long lines.  In addition, the code
	from the Murray Hill and USG sites has been merged in conditionally,
	so that all sites can compile from the same source.]]

Version 2.5 -- May 28, 1979

	A bug which caused the VE sequence not to be sent when exiting
	the editor via :q or :wq from visual has been fixed.

	A bug which caused the command r^Q<ESC> to be weird when it
	was repeated has been fixed.

	The $ command now sets the column for future cursor motions to
	effective infinity.  Thus a `$' followed by up/down cursor motions
	moves at the right margin of each line.

	[[Internal: a bug in conditional compilation without the LISP
	features has been fixed.]]

	Several bugs relating to insert mode and intelligent terminals
	have been fixed:

	A bug which caused inserts on HP/DATAMEDIA like terminals to act
	strangely when the material was inserted immediately before a tab
	has been fixed.

	A bug which caused the insertion of full tabs to not appear to
	insert as many spaces as required (under strange circumstances)
	has been fixed.

	A bug which caused inserts on terminals with insert/delete line
	but no insert/delete character to act strangely if the insert
	caused a line to overflow has been fixed.

	The ``expreserve'' program has been improved; you now will get
	mail if a file is saved for you as a result of your phone being
	hung up accidentally.

Version 2.4 -- May 19, 1979

	A bug during inserts on intelligent terminals which occasionally
	caused double ``~~'' characters on the last few lines of the display
	rather than just single `~' characters has been fixed.

	The w W b B e and E operations in visual now wrap around line
	boundaries.  Thus a sequence of enough w commands will get to any
	word below the current position in the file, and b's will back
	up to any place before.  Thus these are more like the sentence
	operations ( and ).  You still can't back around line boundaries
	duing inserts however.

Version 2.3 -- May 13, 1979

	The P command to ex is now a synonym for p, so that 1,$P works,
	if you don't let up on the shift key soon enough.

	The / and ? operations within visual and open now hit later
	(or earlier resp) occurrences of the same string on the same
	line.  This makes scans using / and ? much more useful.  You
	can move to the right on the current line by typing /pref<ESC>
	where `pref' is a prefix of the word you wish to move to, and
	delete to a following string `str' by doing d/str<ESC> if it is
	on the same or succeeding line.  Previously the command
		d/pat/
	deleted lines through the next line containing `pat'; it now
	deletes text up to the next instance of `pat'.  To delete to
	the next line containing `pat', do
		d/pat/0
	which is short for
		d/pat/+0
	In general if you use an offset after the scanning pattern,
	whole lines will always be affected.

	Several bugs relating to the setting of the previous context mark
	`` have been fixed, including one which caused operations such as
	d`` or c`` to occasionally dump core.  In particular, the operations
		( ) { } [[ ]] and %
	now set the previous context mark correctly, and the mark is set
	even if the motion by these operations lands in the same line.

	More optimization is now done on output cursor motions.  This
	is particularly much better on HP terminals which have
	ridiculously long cursor addressing sequences.  A new
	capability has been added to the termcap file to aid this:
	``bt'' (backtab).  Thanks to Chuck Haley for the new code to
	implement this.

	A bug has been fixed on intelligent terminals which caused part
	of the screen to be accidentally erased during insertions.
	This occurred only on the first line on the screen, when it
	became longer than one displayed line and only if a part of
	the screen (at the top) was currently not in use.

	A bug has been fixed which caused the command ``dp'' to be interpreted
	as ``delete to register p''.  This normally went unnoticed since
	the ``autoprint'' option would cause the effect which the ``p'' was
	forcing.

Version 2.2 -- May 6, 1979

	"d)" now deletes a line if the current line is a sentence rather
	than leaving an empty line.

	The command
		:s/str
	now deletes str if it can find it; previously it was an error.

	The editor now handles multiple ":" escapes correctly; previously
	the screen would not be redrawn necessitating a ^L to fix it if you
	gave a `:!command' to ``[Hit return to continue]''.

	Recursive calls to visual from within open or visual are no longer
	permitted.  Previously ``:vi'' from within open mode would eventually
	leave the editor in a strange state.

	The %age in the status line is now correctly printed on 11's;
	Previously internal 16-bit overflows often caused it to be incorrect.

	The editor now ignores a ":" in front of commands.
	Thus you can say ``:read foo'' within ex.

	A bug which caused commands involving ]] to not be repeatable has
	been fixed.  Previously ``d]]'' followed by ``.'' caused an error.

	"ayw now works correctly.  Previously this silently did nothing.

	Several bugs in "recover" and "ex -r" have been fixed.  Thanks
	to Andy Koenig for the fixes.

	In input mode in open and visual ^V (like tenex) is now equivalent
	to ^Q (which is reminiscent of ITS) superquoting the next character.
	A later version of the UNIX tty driver will implement the standard for
	^S ^Q handshaking and make ^Q unusable.

	There are several typos on page 3 of the ``edit'' manual section:
		s/move "a/delete a/
		s/"a move ./put a/
		/move to copy/s//delete to yank/

Version 2.1 -- April 5, 1979

	Invoking ex via
		ex -l
	now sets "lisp" and "showmatch".  This is suitable for invocations
	from within Franz Lisp.  If you don't like "showmatch", you can
	still use "ex -l", just put the command
		set noshowmatch
	in your .exrc file.