homebrew: make update accept formula names

._ brew update upgrade fix.md

homebrew: make update accept formula names

Homebrew has two commands with similar names - update and upgrade. Update is intended to update brew itself while upgrade is used to update individual formula.

This division is confusing to some.

Therefore here are shell functions for bash and zsh that reroute update to upgrade if a formula name is given.

.bashrc

# Put this into ~/.bashrc

brew() {
    # This makes homebrew accept `brew update <formula>` instead of insisting on `upgrade`.
    # When no parameters are given or all start with a dash it's assumed the user really wanted to use `update`.

    has_name=0
    for word in "${@:2}"; do
        if [[ ! $word =~ -.* ]]; then
            has_name=1
            break
        fi
    done

    if [[ ${@:1:1} == update && $has_name -gt 0 ]]; then
        command brew upgrade "${@:2}"
    else
        command brew "${@}"
    fi
}

.zshrc

# Put this into ~/.zshrc

brew() {
    # This makes homebrew accept `brew update <formula>` instead of insisting on `upgrade`.
    # When no parameters are given or all start with a dash it's assumed the user really wanted to use `update`.

    # Explanation of the condition:
    # - Is the first parameter `update`?
    # - Count the number of array elements that start with `-`
    #   - `(M)` -> remove non matching elements
    #   - `#@[2,-1]` -> count (in this case matching) elements in `@` starting from second until end
    #   - `:#-*` -> match the elements against `-*` and remove non matching ones (due to the `(M)` flag)
    # - Compare the number starting with `-` against the total

    if [[ ${@[1]} == update && ${#@[2,-1]} -gt ${(M)#@[2,-1]:#-*} ]]; then
        echo "Assuming update -> upgrade"
        command brew upgrade "${@[2,-1]}"
    else
        command brew "${@}"
    fi
}