If you have nix (package manager) installed, it takes like half a second. For tools I want to install through nixpkgs I make a starter like this:

    $ cat /usr/local/bin/difftastic
    #!/bin/sh
    source $HOME/.nix-profile/etc/profile.d/nix.sh
    nix run nixpkgs.difftastic -c difftastic "$@"

and then it'll install on first run:

    $ difftastic
    these paths will be fetched (1.17 MiB download, 9.38 MiB unpacked):
      /nix/store/wn74xn0w60xcwsly6nqaibn205hh2qms-difftastic-0.8
    copying path '/nix/store/wn74xn0w60xcwsly6nqaibn205hh2qms-difftastic-0.8' from 'https://cache.nixos.org'...
    Difftastic 0.8.0
    Wilfred Hughes
    A syntax aware diff.
    
    USAGE:
    [etc.]