This is exactly the frustration that lead me to write Rad [0] (the README leads with an example). I've been working on it for over a year and the goal is basically to offer a programming language specifically for writing CLIs. It aims for declarative args (no Bash ops parsing each time), automatic --help generation, friendly (Python-like) syntax, and it's perfect for dev build scripts. I'll typically have something like this:

    #!/usr/bin/env rad
    ---
    Dev automation script.
    ---

    args:
        build   b bool    # Build the project
        test    t bool    # Run tests
        lint    l bool    # Run linter
        run     r bool    # Start dev server
        release R bool    # Release mode
        filter  f str?    # Test filter pattern

        filter requires test

    if build:
        mode = release ? "--release" : ""
        print("Building ({release ? 'release' : 'debug'})...")
        $`cargo build {mode}`

    if lint:
        print("Linting...")
        $`cargo clippy -- -D warnings`

    if test:
        f = filter ? "-- {filter}" : ""
        print("Running tests{filter ? ' (filter: {filter})' : ''}...")
        $`cargo test {f}`

    if run:
        bin = release ? "target/release/server" : "target/debug/server"
        $`./{bin}`


    Usage: ./dev -b (build), ./dev -blt -f "test_auth" (build, lint, test auth), ./dev -r (just run).

[0] https://github.com/amterp/rad