AUSAM/source/S/emchanges0

Main changes to 'ed' (= 'e' = 'em') not listed in the UPM :

1.  New commands :

	a.  tin		will cause an automatic 'w' every n minutes.

	b.  (.,.+1)j	joins the addressed lines together.  The effect is
			as though the end-of-lines had been replaced with
			blanks.  Thus, for example, '1,$jp' turns the file
			into one (long?) line, and prints it.

	c.  (.,.+1)jc	joins the addressed lines together, as above.  The
			difference is that this form 'compresses' the lines,
			leaving only one blank at the join (throws away any
			other blanks or tabs).

	d.  cd pathname	changes the current working directory.  The pathname
			may not contain the short-cuts '%' or '\@'.  Upon
			exit from ed, you will be back where you started.

	e.  ^t and ^p	in open-mode ('o' command) will backup one character
			and skip to the end of the line, respectively.

	f.  z		print the contents of the current search buffer.
			(In case you forgot, or those #'s got too much)

2.  Extensions to existing commands :

	a.  wa filename	appends the editor's buffer onto the end of filename.

	b.  %n or "n or &n	will list n lines around, after, or above dot.
				Default values are such as to fill the screen.
				'n' will be remembered.

	c.  o mode rubouts preserve the line properly even when you have
				inserted 'nl's.

3.  Alterations/Additions :

	a.  The default search-string for global searches has been made '/^/'.
	    Thus 'g', followed by a command, is (almost) equivalent to '1,$',
	    followed by that command.  Thus, for example, 'gp' will print
	    all lines in the file.
	    The difference between 'g' and '1,$' is shown by commands which
	    alter the number of lines - e.g. 'gjc' will join-and-compress
	    every second line to the preceding line, whereas '1,$jc'
	    will join-and-compress all lines into one line.

	b.  The character '&' in a search-string is replaced by the previous
	    search-string, unless escaped with a '\'.

	c.  The '%' in a shell command line is replaced with the current
	    file name, unless escaped with a '\'.

	d.  Labels are maintained on lines affected by s, x, and o commands,
	    and are maintained on the first lines of lines affected by c and
	    j commands.

	e.  Error routine drastically altered.  When ed is invoked in a shell
	    command file, or is fed a file of edit-commands, and an error
	    occurs, the line number at which that error occurred is printed
	    out.  If that error was anything but a match-fail, or a non-
	    existent edit-file, the rest of the input file is skipped.
	    When invoked with a '-' flag, e.g. 'e - filename', match-fail
	    and non-existent edit-file messages are suppressed.
	    The error messages were changed from '?' and '??' to a slightly
	    more verbose message.  This may be suppressed by invoking ed with
	    a '-s' flag : e.g. 'e -s filename'.
	    Match-fails in global searches result in a suitable message.

	f.  All nulls ( = '\0' = chr(0)) in the input file are removed.
	    This was always done - you are now told how many were removed.
	    Generally, this means you blew it - e.g. you tried to edit
	    an a.out, or an obj, or a directory, etc.
	    Also, a line-feed is added onto the last line of the input file
	    if there was not one there.

	g.  Several flags have been added :

		-e	puts ed into 'elfic' mode, which forbids e, f, and w
			commands, forbids an r command not followed by a file
			name, and does an automatic w on quitting.

		-l	executes an 'l' (by default) instead of a 'p',
			when a line number or newline is given without
			a command.

	h.  The construction [seq] now allows ranges. '[a-z]' works as in
	    glob. '-' may be escaped by '\'. Much taedium is releived.



Please note that I am not responsible for all these changes, and have my own
opinion on how useful some of them are ....

						Kevin F. Hill

						  UNSWDCS