Re: Deleting entries in history

[Manfred Lotz <ml_news@posteo.de>]

On Fri, 6 Mar 2020 13:15:10 -0800
Bart Schaefer <schaefer@brasslantern.com> wrote:

> On Fri, Mar 6, 2020 at 11:55 AM Manfred Lotz <ml_news@posteo.de>
> wrote:
> >
> > What is the proper way to delete entries in the history?
> >
> > Just load the history file in an editor, deleting things and save
> > it?  
> 
> The first thing to note is that when $SAVEHIST is nonzero, zsh will
> typically update the file when the shell exits, so anything that is in
> the runtime history of the current shell might reappear even after it
> is deleted from the file.  I say "might" because this is affected by
> the assorted setopts that control how the history is maintained.  The
> only safe way to directly edit the history is to make sure no other
> zsh is running that might rewrite it, and then set SAVEHIST=0 in your
> current shell before doing anything else.
> 

Ok, this means it is best done directly after reboot when I open the
first zsh shell.


> Once you are sure you have done that, then it should be OK to use an
> editor on the history file.  Be aware that multi-line events (such as
> "for" or "while" loops) are stored with lines terminated by backslash,
> so if you start deleting a line that ends in backslash you need to
> also delete all the adjacent lines that end in backslash, up to and
> including the next following line that does NOT end in a backslash.
> Single-line events never contain a backslash.
> 

OK, I can check this. 


> If you are using any of the setopts that store timestamped history
> entries, each event will be prefixed by a ":" command that ends at the
> next ";", with the timestamp between.  You should delete these along
> with the event you want to remove, and avoid altering any that are on
> other event lines.

Yep, I have those.

> 
> All that said ... if the events you want to delete can all be matched
> by some simple patterns, you might want to look into either a
> zshaddhistory hook function, or a setting of the HISTORY_IGNORE
> parameter.

I already use zshaddhistory for some commands I don't want to see in
the zsh history.


Thanks.

-- 
Manfred