05/04/18

I’ve done a bit of work to make a replacement reverse-isearch function, which is in a usable state now.

If you want to use it, see the Reverse isearch section below which now covers it.

09/09/17

If you have already installed and you want to get the right timings in the database, see the installation section again. Fix to issue #18.

This is a small bit of zsh code that stores your history into a sqlite3 database. It improves on the normal history by storing, for each history command:

• The start and stop times of the command
• The working directory where the command was run
• The hostname of the machine
• A unique per-host session ID, so history from several sessions is not confused
• The exit status of the command

It is also possible to merge multiple history databases together without conflict, so long as all your machines have different hostnames.

You will need sqlite3 and the usual coreutils commands installed on your PATH. To load and activate history recording you need to source sqlite-history.zsh from your shell in your zsh startup files.

If you want the history to contain correct timing information, you will also need to run histdb-update-outcome in your precmd hook

Example for installing in $HOME/.oh-my-zsh/custom/plugins/zsh-histdb (note that oh-my-zsh is not required):

mkdir -p $HOME/.oh-my-zsh/custom/plugins/
git clone https://github.com/larkery/zsh-histdb $HOME/.oh-my-zsh/custom/plugins/zsh-histdb

Add this to your $HOME/.zshrc:

source $HOME/.oh-my-zsh/custom/plugins/zsh-histdb/sqlite-history.zsh
autoload -Uz add-zsh-hook
add-zsh-hook precmd histdb-update-outcome

in your zsh startup files.

https://github.com/drewis/go-histdbimport is a useful tool for doing this!

You can query the history with the histdb command. With no arguments it will print one screenful of history on the current host.

With arguments, it will print history lines matching their concatenation.

For wildcards within a history line, you can use the % character, which is like the shell glob *, so histdb this%that will match any history line containing this followed by that with zero or more characters in-between.

To search on particular hosts, directories, sessions, or time periods, see the help with histdb --help.

You can also run histdb-top to see your most frequent commands, and histdb-top dir to show your favourite directory for running commands in, but these commands are really a bit useless.

$ histdb strace
time   ses  dir  cmd
17/03  438  ~    strace conkeror
22/03  522  ~    strace apropos cake
22/03  522  ~    strace -e trace=file s
22/03  522  ~    strace -e trace=file ls
22/03  522  ~    strace -e trace=file cat temp/people.vcf
22/03  522  ~    strace -e trace=file cat temp/gammu.log
22/03  522  ~    run-help strace
24/03  547  ~    man strace

These are all the history entries involving strace in my history. If there was more than one screenful, I would need to say --limit 1000 or some other large number. The command does not warn you if you haven’t seen all the results. The ses column contains a unique session number, so all the 522 rows are from the same shell session.

To see all hosts, add --host after the query terms. To see a specific host, add --host hostname. To see all of a specific session say e.g. -s 522 --limit 10000.

If you use zsh-autosuggestions you can configure it to search the history database instead of the ZSH history file thus:

_zsh_autosuggest_strategy_histdb_top_here() {
    local query="select commands.argv from
history left join commands on history.command_id = commands.rowid
left join places on history.place_id = places.rowid
where places.dir LIKE '$(sql_escape $PWD)%'
and commands.argv LIKE '$(sql_escape $1)%'
group by commands.argv order by count(*) desc limit 1"
    suggestion=$(_histdb_query "$query")
}

ZSH_AUTOSUGGEST_STRATEGY=histdb_top_here

This query will find the most frequently issued command that is issued in the current directory or any subdirectory. You can get other behaviours by changing the query, for example

  _zsh_autosuggest_strategy_histdb_top() {
      local query="select commands.argv from
  history left join commands on history.command_id = commands.rowid
  left join places on history.place_id = places.rowid
  where commands.argv LIKE '$(sql_escape $1)%'
  group by commands.argv
  order by places.dir != '$(sql_escape $PWD)', count(*) desc limit 1"
      suggestion=$(_histdb_query "$query")
}

   ZSH_AUTOSUGGEST_STRATEGY=histdb_top

  }

This will find the most frequently issued command issued exactly in this directory, or if there are no matches it will find the most frequently issued command in any directory. You could use other fields like the hostname to restrict to suggestions on this host, etc.

If you want a history-reverse-isearch type feature there is one defined in histdb-interactive.zsh. If you source that file you will get a new widget called _histdb-isearch which you can bind to a key, e.g.

source histdb-interactive.zsh
bindkey '^r' _histdb-isearch

This is like normal history-reverse-isearch except:

• The search will start with the buffer contents automatically
• The editing keys are all standard (because it does not really use the minibuffer).

  This means pressing C-a or C-e or similar will not exit the search like normal history-reverse-isearch

• The accept key (RET) does not cause the command to run immediately but instead lets you edit it

There are also a few extra keybindings:

• M-j will cd to the directory for the history entry you’re looking at. This means you can search for ./run-this-command and then M-j to go to the right directory before running.
• M-h will toggle limiting the search to the current host’s history.
• M-d will toggle limiting the search to the current directory and subdirectories’ histories

The database lives by default in $HOME/.histdb/zsh-history.db. You can look in it easily by running _histdb_query, as this actually just fires up sqlite with the database.

For inspiration you can also use histdb with the -d argument and it will print the SQL it’s running.

You should be able to synchronise the history using git; a 3-way merge driver is supplied in histdb-merge.

The 3-way merge will only work properly if all the computers on which you use the repository have different hostnames.

The histdb-sync function will initialize git in the histdb directory and configure the merge driver for you first time you run it. Subsequent times it will commit all changes, pull all changes, force a merge, and push all changes back again. The commit message is useless, so if you find that kind of thing upsetting you will need to fix it.

The reason for using histdb-sync instead of doing it by hand is that if you are running the git steps in your shell the history database will be changed each command, and so you will never be able to do a pull / merge.

None, and I’ve used the names with underscores to mean something else.

Happy to look at changes. I did at one point have a reverse-isearch thing in here for searching the database interactively, but it didn’t really make my life any better so I deleted it.