How to make Zsh not store failed command

Problem

I'm using oh-my-zsh and Antigen to manage my Zsh.

Sometimes I will accidentally enter a wrong/failed command into Zsh and it is very annoying when the zsh-autosuggestions plugin throws up these commands.

For e.g., say I typed gut status rather than git status.

Now, as I attempt to type the correct command again, once I typed g, the autosuggestion plugin will throw up gut status as that is the closest match in recent history. But that is a failed command!

What I want to do is to keep these failed commands from "polluting" my history so the autosuggestion plugin will not suggest them.

What I have done

I've searched for this and the closest match to keeping out entries from the history are that of setting HIST_IGNORE_SPACE, or methods to ignore specific commands, or to delete commands manually after entering them. See this and this. But as @Adaephon 52 noted, this takes place after the deed is done.

What I'm considering doing

What I have in mind right now is to write a function that gets triggered every time a failed command is entered into Zsh to delete the latest entry from history. However, I'm not familiar enough with Zsh to know whether this sort of trigger exists or how to go about doing it.

Note on the accepted solution

For those who are interested in this problem, the accepted solution works in the sense that failed commands are not stored in the history file. fc -l or history confirms this.

However, it seems that the zsh-autosuggestions plugin is doing its own local caching of sorts (or is generating suggestions using other mechanism), so it will still suggest the failed commands, but only if the session is not over. When the user starts a new instance of the shell, when presumably the plugin has to load the cached history, it no longer suggests the failed commands (unless you enter them again, of course).

The proposed solution is technically correct as I (mistakenly) framed my question in such a way that it only requires an answer that stops Zsh from storing the failed commands and the accepted solution does that (albeit in a limited way; See link in solution for details).

Anyone who is familiar with shell scripting (I'm not) and motivated enough can check the zsh-autosuggestions script.

Solution 1:

Bart Schaefer proposed the following approach to the same question on the zsh users mailing list:

 zshaddhistory() { whence ${${(z)1}[1]} >| /dev/null || return 1 }

This function is executed before the command line is written to history. If it does return 1, the current command line is neither appended to the history file nor to the local history stack. However, the check if the command will trigger a command not found error covers only simple cases. E.g. this line will be on the history:

echo foo; echooo bar

But it works fine for your example

gut status

Please be aware, that the wrong command will show up upon UP-ARROW (so that you can correct it!), but is not in the history stack; check with fc -l.

Solution 2:

The built-in fc command supports editing your history. In case you mistyped e.g. the previous command you can enter the following:

$ fc -e nano -1

You can replace nano with the command of your preferred editor. Also you can set the EDITOR variable (parameter) in your zsh config. (See referring SO page)

You need to save the file (the one, created in a system temp. folder, by fc). After it you will end up with the line(s) edited. Enter will run it or you can press Ctrl+C to finish your editing.

For further details see zsh documentation: Zsh: editing history

In case you want to edit the entire history

$ fc -W; nano "$HISTFILE"; fc -R

...again replace nano if you wish

It simply writes out the history -including the cache- then opens the file with an editor.

Please note that zsh knows three types of history:

• Internal: commands you entered since log-in
• Local: the one available within the active shell - [HISTFILE + Internal]
• "Global": it depens but let say it's the file set in HISTFILE

Please bear in mind that in case your history file is shared (SHARE_HISTORY) and you have more than one zsh shell opened with the user in question then you better run the fc -W command in those shells first. Once you finished with the edit then run fc -R. Otherwise the commands entered within those shells won't be stored and then recognized your manual edit of the HISTFILE.