Overview of Shell Autocompletions

I simply love shell completion on the command line, which saves you from a lot of spelling errors and therefore saves you a lot of time in your daily working. With Autocompletion you can press <TAB> when you're typing a command, and the shell will show you what the options are.

But Shells like my beloved bash or the Z Shell (zsh) don't provide this feature by themself, because they don't know which options are available. For this a lot of scripts exist, that teach the different options to your Shell. In this article I will list the Autocompletion scripts I use in my envrionments and show you how to install them.

Prerequisites

Brew

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

echo 'eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"' >> ~/.bash_profile
eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"

sudo apt-get install -y build-essential

brew install gcc

Bash Autocompletion

First install the package bash-completion using Homebrew:

brew install bash-completion

echo '[[ -r "/usr/local/etc/profile.d/bash_completion.sh" ]] && . "/usr/local/etc/profile.d/bash_completion.sh"' >> ~/.bash_profile

Z Shell Autocompletion

First install the package bash-completion using Homebrew:

brew install zsh-completions

After finishing this installation, you'll get some instructions similiar to the following, which you'll need to follow. After this the setup for zsh is completed.

  if type brew &>/dev/null; then
    FPATH=$(brew --prefix)/share/zsh-completions:$FPATH

    autoload -Uz compinit
    compinit
  fi

You may also need to force rebuild `zcompdump`:

  rm -f ~/.zcompdump; compinit

Additionally, if you receive "zsh compinit: insecure directories" warnings when attempting
to load these completions, you may need to run this:

  chmod go-w '/usr/local/share'

Kubectl

Bash

If you want to enable kubectl Autocompletion for your current user only use:

echo 'source <(kubectl completion bash)' >> ~/.bashrc

If you want to enable the Autocompletion system-wide for every user use:

kubectl completion bash | sudo tee /etc/bash_completion.d/kubectl > /dev/null

If you have an alias for kubectl like k, you can extend shell completion to work with that alias as well:

echo 'alias k=kubectl' >> ~/.bashrc
echo 'complete -F __start_kubectl k' >> ~/.bashrc

Z Shell (zsh)

You can enable the kubectl Autocompletion for zsh for your user using:

echo 'source <(kubectl completion zsh)' >> ~/.zshrc

Kubectx and Kubens

Kubectx and kubens are probably the most useful krew plugins you can use in your Kubernetes environment.

Bash

git clone https://github.com/ahmetb/kubectx.git ~/.kubectx
COMPDIR=$(pkg-config --variable=completionsdir bash-completion)
ln -sf ~/.kubectx/completion/kubens.bash $COMPDIR/kubens
ln -sf ~/.kubectx/completion/kubectx.bash $COMPDIR/kubectx
echo 'export PATH=~/.kubectx:$PATH' >> ~/.bashrc

Z Shell (zsh)

mkdir -p ~/.oh-my-zsh/completions
chmod -R 755 ~/.oh-my-zsh/completions
ln -s /opt/kubectx/completion/_kubectx.zsh ~/.oh-my-zsh/completions/_kubectx.zsh
ln -s /opt/kubectx/completion/_kubens.zsh ~/.oh-my-zsh/completions/_kubens.zsh

Helm

Bash

To load completions in your current shell session:

source <(helm completion bash)

To load completions for every new session, execute as root user:

helm completion bash > /etc/bash_completion.d/helm

Z Shell (zsh)

To load completions in your current shell session:

source <(helm completion zsh)

To load completions for every new session, execute as root user:

helm completion zsh > "${fpath[1]}/_helm"

Operator SDK

Bash

To load completions in your current shell session:

source <(operator-sdk completion bash)

To load completions for every new session, execute as root user:

operator-sdk completion bash > /etc/bash_completion.d/operator-sdk

Z Shell (zsh)

source <(operator-sdk completion zsh)

To load completions for every new session, execute as root user:

operator-sdk completion zsh > "${fpath[1]}/_operator-sdk"

Velero

Velero is the most-versatile solutions for backup and disaster recovery management in a Kubernetes environment. With these commands you can easily set-up autocompletion.

Bash

For your current user simply type:

echo 'source <(velero completion bash)' >>~/.bashrc

If you want to enable it system-wide use:

sudo velero completion bash >/etc/bash_completion.d/velero

When you are using a shortcut for velero you need to activate the autocompletion for this shortcut as well:

echo 'alias v=velero' >>~/.bashrc
echo 'complete -F __start_velero v' >>~/.bashrc

Z Shell (zsh)

Instead of using the .bashrc you need to use .zshrc for the Z Shell:

echo 'source <(velero completion zsh)' >> ~/.zshrc

echo 'alias v=velero' >>~/.zshrc
echo 'complete -F __start_velero v' >>~/.zshrc

Terraform

Bash and Z Shell (zsh)

Terraform makes it very easy to use Autocompletion as it comes with a simple cli command:

terraform -install-autocomplete

After installation you need to restart your shell.