Export commands that I have created

Is there a way to export commands that I have created, so that I can use them on a different computer running DOpus rather than having to create them all over again?

Go to customize, select the button command you want, right click and choose COPY.

Then in Notepad or any other text editor paste the code into a new file and take that file to the other computer where you copy the Opus button code in the Notepad file to the Windows clipboard and then with Opus in customize mode, you paste it onto a toolbar.

Settings->Backup & Restore is your best friend...

While in Customize mode you can also drag individual buttons to your desktop to create .DCF files which you can drag back to a toolbar to create the same button. (The content of the .DCF file will be the same, or nearly the same, as what you'll get using John's copy & paste method.)

Toolbars are also just .DOP XML (text) files which you can find in /dopusdata/Buttons if you want to backup an entire toolbar without also backing up all of your Opus settings using Steje's method. Of course there isn't much reason not to backup everything! I'm just mentioning this in case you want to share a toolbar with other people.