Re: from the old vi faq

Eli the Bearded wrote:

> http://www.faqs.org/faqs/editor-faq/vi/part2/
> ------ start quote 8< ------
> 6.1 - Silly vi tricks
> Note: Also check out the Silly macros down below. Many macros and
> tricks are interchangeable.
>
> xp This will delete the character under the cursor, and put it
> afterwards. In other words, it swaps the location of two characters.
>
> ddp Similar to xp, but swapping lines.
>
> yyp duplicate a line
>
> uu Undo and redo last change. (This will take you to the last
> modification to the file without changing anything.) You can also use
> this to compare the changes to a line. Make the changes to the line,
> press U to undo the changes to the current line, and then press u to
> toggle between the two versions.
>
> :g/.*/m0
> This will reverse the order of the lines in the current file.
> m0 is the ex command to move the line to line 0.
>
> :v/./d or :g/^$/d
> Removes all blank lines.
>
> :g/^[ <ctrl-v><tab>]*$/d
> Removes all lines that only have whitespace.
>
> :v/./$s/$/<ctrl-v><enter>./|'';/./-1j|$d
> Replaces multiple blank lines with just one blank line.
> ------ >8 end quote ------
>
> All of that works in vim (save "uu" with modern undo settings), except
> for the last one. I happen to have true vi handy ("Version 4.0 (gritter)
> 3/25/05"), as well as nvi ("Version (1.81.6-2013-11-20nb3)"), elvis
> ("2.2.0"), vim 7.4, and vim 8.1.
>
> The replace multiple blank lines works in true vi and nvi, but not in
> elvis or either vim. The trick works by the :v/./ selecting a group of
> lines, $s editing the last line in that group to be a blank line and a
> line with a dot, then |'' returning to the first line in the group, /./-1j
> joining all but the last line of the group (so as not to join the new
> dot line), and finally |$d deleting that last dot line. It's a
> seriously complicated "trick", with lots of subtle compatibility tests
> built right in.
>
> Is this a known incompatiblity in vim? I don't recall seeing it
> documented. And I sought out that FAQ precisely for that trick since I
> recalled it existed, but not what it was.

AFAIK this builds upon a bug in Vi. In Nvi Keith Bostic decided to keep
it like that (perhaps because of this example). I decided that it's
really an unintentional bug and did not replicate it.

Using "$" after :v does not refer to "the last in a a group", since :v
works on a per-line base, it marks every line not matching the pattern.
So in Vim the "$" refers to the last line, and changes that.

There are much simpler ways to collapse multiple blank lines.

--
hundred-and-one symptoms of being an internet addict:
122. You ask if the Netaholics Anonymous t-shirt you ordered can be
sent to you via e-mail.

/// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net \\\
/// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\ an exciting new programming language -- http://www.Zimbu.org ///
\\\ help me help AIDS victims -- http://ICCF-Holland.org ///

--
--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php

---
You received this message because you are subscribed to the Google Groups "vim_use" group.
To unsubscribe from this group and stop receiving emails from it, send an email to vim_use+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.