bash auto-completion on Linux

Some optional configuration for bash auto-completion on Linux.

Introduction

The kubectl completion script for Bash can be generated with the command kubectl completion bash. Sourcing the completion script in your shell enables kubectl autocompletion.

However, the completion script depends on bash-completion, which means that you have to install this software first (you can test if you have bash-completion already installed by running type _init_completion).

Install bash-completion

bash-completion is provided by many package managers (see here). You can install it with apt-get install bash-completion or yum install bash-completion, etc.

The above commands create /usr/share/bash-completion/bash_completion, which is the main script of bash-completion. Depending on your package manager, you have to manually source this file in your ~/.bashrc file.

To find out, reload your shell and run type _init_completion. If the command succeeds, you’re already set, otherwise add the following to your ~/.bashrc file:

source /usr/share/bash-completion/bash_completion

Reload your shell and verify that bash-completion is correctly installed by typing type _init_completion.

Enable kubectl autocompletion

You now need to ensure that the kubectl completion script gets sourced in all your shell sessions. There are two ways in which you can do this:

• Source the completion script in your ~/.bashrc file:

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

• Add the completion script to the /etc/bash_completion.d directory:

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

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

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

Note: bash-completion sources all completion scripts in /etc/bash_completion.d.

Both approaches are equivalent. After reloading your shell, kubectl autocompletion should be working.