Thank you for all your ideas. I have now tried all the suggestions for sudo. Result is "permission denied"
Tried visudo. It said something about "You have probably been given the usual lecture about ..." Then it let me give myself a password. I thought this would be a root password, so I tried it out by attempting to correct the clock, which is not set for my timezone. It did not work-it said the password was invalid.
I also tried the command starting with "dig>>". This was an unrecognizable command.
Command starting with "cat" was also unrecognizable
In answer to the
question about what my laptop uses to connect to the internet, it uses Network Manager.
Somebody said he has an old laptop, perhaps a vintage like mine, and it does not support wlan networks. I suspect that might be what I have at home.