Thanks Icy for pointing this out.
I'm new to Mathematica so I was delighted to read that its user interface supports command completion. However, that page is silent about the fact that Wolfram Predictive Interface is not available on Raspi. Not knowing this, I failed to use or enable Suggestions Bar or Input Assistant. I was puzzled. I thought my installation was defective or my configuration wrong. So I was about to post a question on this community to this regard when I found your posting. Further research unearthed a seven year old community posting that described the limitations of Mathematica running on Raspi. Computing power and RAM size have since increased considerably on the Raspberry Pi platform.
For beginners like me, input assistants (i.e. command suggestions, autocompletion, etc.) are invaluable for flattening the learning curve.
