Re: macro question

[Thomas Dickey]

On Sat, Apr 06, 2024 at 07:21:33PM +1100, Brendan O'Dea wrote:
> On Fri, 5 Apr 2024 at 16:09, david sowerby <d_sowerby@yahoo.com> wrote:
> > Hi, in Vim/Neovim I can save a copy of the file when I exit. The copy is 
> > renamed file-$(date +%s).bak. This gives me a file with an increasing 
> > number plus .bak. It looks like "date+%s" and  "&stime" do the same thing. 
> > Is this possible in vile? I know I can save a file as file.bak but I like 
> > to save a series of changed files, not just one.
> 
> I vaguely recall dealing with operating systems which did this (VMS?
> MVS?).  Every file save added a new version, and you had to
> periodically run `PURGE` to recover disk space.

VMS (DEC) is what you're thinking of.
MVS (IBM) is different...

I wrote a file-manager for VMS in 1984-1985,
which implements a command language with "purge":

https://invisible-island.net/flist/flist.html
https://github.com/ThomasDickey/flist-snapshots/blob/1eeef2322704c5efe0f98b1b287c16a896657f0b/doc/flist.mem#L64

and during the initial development was able to generate a series of versions
for the executable that passed 1200.
 
> An alternative is to stash each write in a version control system.
> In a previous job (more than a decade ago, before git existed), all of
> our production servers had the attached script installed as both `viw`
> (update file and send diff), and a link as `vis` (silently update
> file).  This logged changes to any production files (typically in
> /etc), and stashed them in version control so you could easily revert
> a problem change; see the difference b/w versions, etc.

VMS had a versioning system also - "CMS", which I encountered in 1989.
Its archive files looked like SCCS (interleaved deltas), except that the
magic character was "*" rather than control/A.  With some work, one could
determine when it was introduced:

http://www.bitsavers.org/pdf/dec/vax/vms/

It's mentioned in the master index for 5.0 (1988).

http://www.bitsavers.org/pdf/dec/vax/vms/5.0/

(VMS DEC/CMS is unrelated to IBM VM/CMS)

Nowadays, I generally review changes in vile (showing diff's in a buffer).
That's usually with RCS, with Git for special cases (and snapshots).

https://invisible-island.net/ded/cm_tools.html
https://invisible-island.net/personal/git-exports.html

(There are of course graphical diff's - sometimes helpful, sometimes not)
 
> Note that this script will prompt for a description of the file on
> first commit, and a reason for the change in subsequent updates.
> 
> This worked pretty well for us at the time, and didn't version every
> file, just the ones we cared about.
> 
> --bod



-- 
Thomas E. Dickey <dickey@invisible-island.net>
https://invisible-island.net

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