Don't add current command to history (`ignore` flag)

[martin-braun]

What do you want?

Running a command without it being added to the history in the first place (sort of, it shall be added, but removed instantly). This would be great, as it would allow to send a single command in incognito without the necessity to send a hist d -1 afterwards.

Why do you want this?

I have so send a secret to my Android phone via USB debugging (adb shell -n input text), because the TAN2GO app of my bank won't allow me to paste in passwords from my password manager. Flawed design. I then want to prevent the secret in my history.

Who else would benefit from this?

Anybody who wants to send a single command and delete it from history in one go, i.e. when having the command on the password manager like I do. Right now, sending adb shell -n input text mysecret; hist d -1 will not remove the secret, but the history entry prior. So the user has to send two commands.

How should it work?

Given this situation: A new flag to secretly send a command and remove it from history afterwards, let's call it ignore/i?

When I perform these steps: hist ignore echo secret

Then I expect this to happen: It should print secret without adding echo secret to the history.

Thanks!

[marlonrichert]

That's already possible in Zsh natively. You have three options for this, all of which can be combined:

• Add setopt HIST_IGNORE_SPACE to your .zshrc file. Then, if you insert at least one space at the very beginning of a command line, it will not be saved to history, although it is still saved to local history in memory.
• Add HISTORY_IGNORE=<glob pattern to your .zshrc file. Then, any command line that matches that pattern will not be saved to history.
• Add a history hook function to your .zshrc file:

  autoload -Uz
  <function>() {
  <logic>
  }
  add-zsh-hook zshaddhistory <function>

  Then, whenever you submit a command line, before it is executed, it will be passed to this function. If the function returns 1, it will not be saved. If it returns 2, it will be saved to local history in memory, but will not be saved to the $HISTFILE. Returning 0 will save the command line to history, unless prevented by one of the other two options.

[martin-braun]

@marlonrichert Thank you for the detailed explanation, it makes sense to do it this way. Very useful.