Starting from the situation that I don't have octave installed, I get:
...
$ octave
If 'octave' is not a typo you can use command-not-found to lookup the package that contains it, like this:
    cnf octave
...

Following the cnf suggestion, I get a package install suggestion:
...
$ cnf octave
                        
The program 'octave' can be found in the following package:
  * octave-cli [ path: /usr/bin/octave, repository: zypp (repo-oss) ]

Try installing with:
    sudo zypper install octave-cli
...

Following the package install suggestion, I get the octave command:
...
$ sudo zypper install octave-cli
  ...
(1/1) Installeren van: octave-cli-5.1.0-lp151.1.15.x86_64 ................................................[gereed]
...

However, I get:
...
$ octave -q
/usr/lib64/octave/5.1.0/exec/x86_64-suse-linux-gnu/octave-gui: failed to exec '/usr/lib64/octave/5.1.0/exec/x86_64-suse-linux-gnu/octave-gui'
octave: No such file or directory
...

I can work around this by doing
...
$ DISPLAY= octave -q
octave:1> 
$
...

This worked without a problem in leap 42.3 and 15.0, but fails in 15.1 and tumbleweed.