How To Set Up History-Based Autocompletion in Zsh

Yes, Oh My Zsh is awesome! That’s the first thing I installed when I switched from Bash to Zsh and I used it for a few years.

Past that time, I realized that in my daily use, the only features I was taking advantage was:

• Autocompletion and history-based autocompletion using the arrow keys.

• The fancy multi-line and colorful user prompt showing the working directory, and the switching color after the fail/success of the previous command execution.

• The git repository info at the user prompt.

• The z command, provided by the ZSH-z plugin.

I couldn’t help myself but thinking that the Oh My Zsh framework was much more than I needed. I decided to remove Oh My Zsh and reset Zsh from scratch, so I could configure and install only the features I needed.

This is a four-part post series explaining how to set up those features on a fresh new Zsh installation:

Customize Zsh Pt.1 - Autocompletion 👈

Customize Zsh Pt.2 - User Prompt

Customize Zsh Pt.3 - Git Info

Customize Zsh Pt.4 - ZSH-z Plugin

Autocompletion

Zsh has a powerful completion system built-in by default. You need to load and initialize to take advantage of it. There is a lot to learn about it if you feel like going deeper but this post’s objectives are:

• To enable the standard autocompletion.

• To set up history-based autocompletion.

How to Set Up

After a Zsh fresh install it runs a helper for the first time you log into the shell:

This is the Z Shell configuration function for new users,
zsh-newuser-install.
You are seeing this message because you have no zsh startup files
(the files .zshenv, .zprofile, .zshrc, .zlogin in the directory
~).  This function can help you with a few settings that should
make your use of the shell easier.

You can:

(q)  Quit and do nothing.  The function will be run again next time.

(0)  Exit, creating the file ~/.zshrc containing just a comment.
     That will prevent this function being run again.

(1)  Continue to the main menu.

--- Type one of the keys in parentheses --- 

Avoid using the helper and apply the settings inside the .zshrc file, so:

• Type 0 to exit the Zsh helper creating a blank .zshrc file in your $HOME directory.

• To load and initialize the Zsh completion system, open the .zshrc file in your code editor and add the following line at the top of the file:

# AUTOCOMPLETION

# initialize autocompletion
autoload -U compinit && compinit

(Learn more: man zshcompsys and go to Use of compinit)

• To allow history-based autocompletion, first, apply some configurations to improve Zsh’s history management by adding the following lines to the .zshrc file:

# history setup
setopt SHARE_HISTORY
HISTFILE=$HOME/.zhistory
SAVEHIST=1000
HISTSIZE=999
setopt HIST_EXPIRE_DUPS_FIRST

(Read options and parameters descriptions: man zshoptions and man zshparam)

• With Zsh history set, create key bindings to use up and down arrow keys to navigate history for the provided command:

# autocompletion using arrow keys (based on history)
bindkey '\e[A' history-search-backward
bindkey '\e[B' history-search-forward

The code above assumes that [A is the value your terminal emulator sends for the keyboard up arrow, and that [B is the value for the keyboard down arrow.

You can double check by pressing <Ctrl> + v and <up-arrow> in your Zsh prompt, see more here.

(Learn more: man zshzle and go to ZLE BUILTINS for key bindings, and go to history-search-.)

• Source the .zshrc file again, in the Zsh shell type:

source ~/.zshrc

Autocompletion is ready to go!

The final .zshrc file must look like this:

# AUTOCOMPLETION

# initialize autocompletion
autoload -U compinit
compinit

# history setup
setopt APPEND_HISTORY
setopt SHARE_HISTORY
HISTFILE=$HOME/.zhistory
SAVEHIST=1000
HISTSIZE=999
setopt HIST_EXPIRE_DUPS_FIRST
setopt EXTENDED_HISTORY

# autocompletion using arrow keys (based on history)
bindkey '\e[A' history-search-backward
bindkey '\e[B' history-search-forward

# GENERAL

# (bonus: Disable sound errors in Zsh)

# never beep
setopt NO_BEEP

With those simple steps autocompletion is ready and your Zsh shell is becoming more powerful.

Part 2 explores how to apply a simple configuration to improve the user prompt.

Next:

Customize Zsh Pt.2 - User Prompt

Useful links & references:

• Zsh Documentation (man -k zsh to list each Zsh man page section)

• key bindings table?

• A Guide to the Zsh Completion With Examples

Footnotes:

• This post appeared first at alldrops.info.

• Follow me on Twitter to get more posts like this and other quick tips in your feed.

• If you have any doubts or tips about this post, I’d appreciate knowing and discussing it in the comments section.

• As English is not my native language, I apologize for the errors. Corrections are welcome.

• Big thanks 🙌 to Eric Nielsen for pointing out some improvements in Zsh history settings.