Safe Install - specify dependencies to install. Verify they don't exist first. Verify they DO exist when we're done.

safe-install.sh

#!/bin/bash
set -e # exit when a command fails, so we don't continue doing next steps!

function check_exists {
    CMD="$1"
    # "type" works nicely for checking existence of both shell functions and scripts/bins
    if type -t "$CMD" 1> /dev/null 2>/dev/null; then
        true
    else
        false
    fi
}

function refresh_profile {
    source ~/.bash_profile
}

function safe_install {
    NAME="$1"
    EXISTING_CMD_TO_CHECK="$2"
    INSTALLATION_CMD="$3"

    echo "🔍  Checking for existence of $NAME... (Errors here are expected)"
    if check_exists "$EXISTING_CMD_TO_CHECK"; then
        echo "☑️  Skipping $NAME, found existing installation."
    else
        echo "⬇️  Installing $NAME..."
        if eval $INSTALLATION_CMD; then
            echo "Installing $NAME completed."
            echo "🔁 Refreshing PATH in this subshell..."
            refresh_profile
            if check_exists "$EXISTING_CMD_TO_CHECK"; then
                echo "✅ Install of $NAME: Verified!"
            else
                echo "⏺ Installed $NAME, but couldn't verify install. Quitting."
                exit 1
            fi
        else
            echo "😢 Error installing $NAME - Exiting before making more changes."
            exit 1
        fi
    fi
}

refresh_profile # load up any existing shell functions/PATH stuff

# syntax:
# safe_install "<readable name>" "<existing command to check if installed>" '<install command>'
# Example: safe_install "SDKMAN" "sdk" 'curl -s "https://get.sdkman.io" | bash'