Enable Docker.app completions in zsh, bash, or fish shells on macOS.

link_docker_completions.sh

#!/bin/bash

# Enable Docker.app completions in shells
#
# @param string $shell The shell to load completions for. Accepts "zsh", "bash", "fish". Default current shell.
function link_docker_completions() {
    local shell="${1:-$(basename "$SHELL")}"
    local etc="/Applications/Docker.app/Contents/Resources/etc"
    local share_path="/usr/local/share/${shell}"
    local completions_path

    case $shell in
        zsh)
          completions_path="${share_path}/site-functions"
          ;;

        bash)
          completions_path="${share_path}-completion/completions"
          ;;

        fish)
          completions_path="${share_path}/vendor_completions.d"
          ;;

        *)
          echo -n "No completions available for ${shell}"
          ;;
    esac

    if [[ -n "${completions_path}" ]]; then
        print "Linking completions for ${shell} into ${completions_path}\n"
        find "${etc}" -type f -name "*.${shell}-completion" -exec ln -sf {} "${completions_path}/" \;
    fi
}