How do I make the vi editor display line number

How do I make the vi editor display or hide line numbers?
To make vi display line numbers, you need to set the number flag.

Press the Esc key if you are currently in insert or append mode.
Press : (the colon). The cursor should reappear at the lower left corner of the screen next to a : prompt.
Enter the command: set number
To turn off line numbering, again follow the preceding instructions, except this time enter set nonumber the : prompt:

Using TV for shooting surfing

Using TV for shooting surfing.

Was watching a show that had something to do with surf(ing) photography, when I saw this

30yr surf photography vet to new surf photographer,

30yr guy : “are you shooting in manual mode ?”
new guy : “yeah”
30yr : “I always shoot in Tv, the camera is 10 times smarter than I am”

Tv is Shutter-Priority mode, you set the shutter speed and the camera automatically sets the aperture value to suit.
Tv stands for Time Value

Thanks,
Malcolm