Suppose I define
Octave:1>s = "hello";
Octave:2>mkdir s
Octave:3>cd s
This creates a directory named s (instead of hello), and changes to that directory. How to use hello instead?
mkdir(s)
cd(s)
Take a look at functional vs command syntax: https://octave.org/doc/v5.2.0/Commands.html
commands site:octave.org/doc/v5.2.0/ in duckduckgo to see what results come out!