a safer undo

[Michael Neumann]

Matthew Dillon wrote:
:Hi,
:
:I find myself the utility "undo" very dangerous, as it removes history.
:I'd instead suggest a soft-undo mode by default, which reverts to the
:last version of that file, but keeps the history, i.e. it overwrites the
:file with the content of the old. To really undo, there would be a "-f"
:(force) option, which removes forever the latest version and moves back
:to the last version.
:
:It's so easy to forget the "-d" if you want a diff output, and then, the
:file is gone.
:
:Other than that, a great utility. It's a great way to have version
:control for configuration files built-in from the very beginning.
:
:Regards,
:
:   Michael
    Hmm.  Doesn't it output to stdout by default?  Are you telling it
    to overwrite the original file with '-o <same_file_name>' ?
    Even if you do the original isn't lost.  Undo has no ability to
    remove the file's history.
test# echo abc > x
test# sync
test# sync
test# echo def > x
test# sync
test# sync
Ah, I forgot to sync, so I guess the file hasn't reached the drive and
as such history was lost!
Regards,

  Michael