sudo softwareupdate <cmd> [<args> ...]

** Manage Updates:
        -l | --list             List all appropriate update labels (options:  --no-scan, --product-types)
        -d | --download         Download Only
        -i | --install          Install
                <label> ...     specific updates
                -a | --all              All appropriate updates
                -R | --restart          Automatically restart (or shut down) if required to complete installation.
                -r | --recommended      Only recommended updates
                     --os-only  Only OS updates
                     --safari-only      Only Safari updates
                     --stdinpass        Password to authenticate as an owner. Apple Silicon only.
                     --user     Local username to authenticate as an owner. Apple Silicon only.
        --list-full-installers          List the available macOS Installers
        --fetch-full-installer          Install the latest recommended macOS Installer
                --full-installer-version        The version of macOS to install. Ex: --full-installer-version 10.15
        --install-rosetta       Install Rosetta 2
        --background            Trigger a background scan and update operation

** Other Tools:
        --dump-state            Log the internal state of the SU daemon to /var/log/install.log
        --evaluate-products     Evaluate a list of product keys specified by the --products option 
        --history               Show the install history.  By default, only displays updates installed by softwareupdate.  
        --all                   Include all processes in history (including App installs) 

** Options:
        --no-scan               Do not scan when listing or installing updates (use available updates previously scanned)
        --product-types <type>          Limit a scan to a particular product type only - ignoring all others
                Ex:  --product-types macOS  || --product-types macOS,Safari 
        --products              A comma-separated (no spaces) list of product keys to operate on. 
        --force                 Force an operation to complete.  Use with --background to trigger a background scan regardless of "Automatically check" pref 
        --agree-to-license              Agree to the software license agreement without user interaction.

        --verbose               Enable verbose output
        --help                  Print this help

sudo softwareupdate -l

sudo softwareupdate -ia

sudo softwareupdate --install-rosetta

% sudo softwareupdate --history
Display Name                                       Version    Date                  
------------                                       -------    ----                  
Command Line Tools for Xcode                       13.0       12/08/2021, 19:13:14  
Command Line Tools beta 4 for Xcode                13.0       12/08/2021, 19:13:14  
Command Line Tools for Xcode                       13.1       12/08/2021, 19:13:14

sudo softwareupdate --fetch-full-installer --full-installer-version 10.15.4