Try fdisk -l.........................

The fdisk command is very powerful and as the warning on that link
states, one typing error can erase your data !! What was the reason
for looking up fdisk ?

There are graphical partition managers now that have safety features
so you'd be hard pressed to accidentally damage data or select the
wrong drive so I'd suggest using those rather than fdisk.

Try

sudo fdisk -l /dev/sda

to display the partition table of your first hard drive. ("-l" is for "list".
"Ell", not "eye", or "one".) "/dev/sda" is the "device" it's asking your to
specify. (By the way: your man page link points to "sfdisk", not "fdisk".)

The reason I was doing it is because a friend of my using raspberry pi
tried it and didnt get anything so I tried it.
Oddly, I didnt either.
After last night I rebooted my computer and it worked this morning.
And just so you know, the only thing I did was hit the up arrow after
starting the command line from last night
to show me the last command entered - and it worked.
I think my hard drive is about at the end of its life. Its a older one and
Ive had various other issues with it in the past.