How to remove the last command (or current command for bonus) from zsh history

command historyzsh

Sure there's a super simple smart way to do this, but since history in zshell seems to be aliased to fc, there's no way to use the tricks mentioned in How to remove a single line from history?.

Any pointers on how to do this? My use case would be to remove the last issued command from history so it stops autocompleting (mostly when you've mistyped something and it keeps showing up).

I know I can get the last issued command by doing

history | tail -n 1, but history -d doesn't work and I can't find proper documentation for zsh.

Best Answer

Zsh doesn't offer a real history edition facility. The command history is basically read-only. All you can do is replace it wholesale.

To edit the command line history:

Save it to a file: fc -W
Edit the file
Load the history from the file: fc -R

You can choose the file name by setting HISTFILE.

Untested code:

remove_last_history_entry () {
  setopt local_options extended_history no_hist_save_no_dups err_return

  local HISTFILE=~/.zsh_history_tmp_$$ SAVEHIST=$HISTSIZE
  fc -W
  ed -s $HISTFILE <<EOF >/dev/null
d
w
q
EOF
  fc -R
}

Examples

$ history -E
    1   2.12.2013 14:19  history -E

$ history -i
    1  2013-12-02 14:19  history -E

$ history -D
    1  0:00  history -E
    2  0:00  history -i

If you do a man zshoptions or man zshbuiltins you can find out more information about these switches as well as other info related to history.

excerpt from zshbuiltins man page

Also when listing,
  -d     prints timestamps for each command
  -f     prints full time-date stamps in the US `MM/DD/YY hh:mm' format
  -E     prints full time-date stamps in the European `dd.mm.yyyy hh:mm' format
  -i     prints full time-date stamps in ISO8601 `yyyy-mm-dd hh:mm' format
  -t fmt prints time and date stamps in the given format; fmt is formatted 
         with the strftime function with the  zsh extensions described for 
         the %D{string} prompt format in the section EXPANSION OF PROMPT 
         SEQUENCES in zshmisc(1).  The resulting formatted string must be no 
         more than 256 characters or will not be printed.
  -D     prints elapsed times; may be combined with one of the options above.

Debugging invocation

You can use the following 2 methods to debug zsh when you invoke it.

Method #1

$ zsh -xv

Method #2

$ zsh
$ setopt XTRACE VERBOSE

In either case you should see something like this when it starts up:

$ zsh -xv
#
# /etc/zshenv is sourced on all invocations of the
# shell, unless the -f option is set.  It should
# contain commands to set the command search path,
# plus other important environment variables.
# .zshenv should not contain commands that produce
# output or assume the shell is attached to a tty.
#

#
# /etc/zshrc is sourced in interactive shells.  It
# should contain commands to set up aliases, functions,
# options, key bindings, etc.
#

## shell functions
...
...
unset -f pathmunge _src_etc_profile_d
+/etc/zshrc:49> unset -f pathmunge _src_etc_profile_d

# Created by newuser for 4.3.10

Zsh History – Command History in Zsh

Zsh stores input lines (possibly with time information) in the file indicated by the variable HISTFILE. This should be an absolute file name (otherwise it will be interpreted relative to whatever directory is current at the time).

Zsh has no built-in default value for HISTFILE. The zsh distribution comes with a setup wizard for new users which has the value ~/.histfile built in, so this is what zsh users get by default. Oh-my-zsh comes with HISTFILE=.zhistory preset. So it looks like you tried zsh both with the default setup and with oh-my-zsh. Check your .zshrc (or the file dates) to see which one you're currently using.

How zsh opens the file, and therefore what happens if it is a symbolic link, depends on several options.

If one of the options append_history (set by default), inc_append_history or share_history is set, or when the history is saved explicitly with fc -AI, zsh appends to the existing file.
Note that even under these settings, zsh occasionally overwrite the file as described below to trim it down to size.
Otherwise, if the option hist_save_by_copy is set (it's set by default since zsh 5.0, but does not exist in 4.2), zsh writes a temporary file then moves it in place when complete. In this case, if the history file was a symbolic link, the new file replaces the symbolic link.
Otherwise zsh overwrites the existing file in place.

Rather than point zsh to a symbolic link, set HISTFILE to wherever you want the history file to be.

How many lines of history are kept is configured through the variables HISTSIZE and SAVEHIST. HISTSIZE is the maximum number of lines that are kept in a session and SAVEHIST is the maximum number of lines that are kept in the history file.

To get some history saved at all, you need to set both HISTFILE and SAVEHIST, as the default value of SAVEHIST is 0. You may want to increase HISTSIZE as well (as of zsh 5.0, the default is only 30).

Best Answer

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