Software Update on my mac not working

I opened the terminal and typed software update -/ and this came up:

[Mike-computer-4:~] michaelmundell% softwareupdate -/

softwareupdate: invalid option -- /

usage: 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

--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

[Mike-computer-4:~] michaelmundell% 

Yes. I have restarted the computer, to no avail.

No. 11.6.6, as I said in the post. I am trying to update to .7.

So I did that and the line came up" finding available software", then nothing more.

That did it. I was able to download the update in safe mode.

Thanks to you and Matt for your suggestions.