Understanding ampersand (&) usage in the command

Shell Programming and Scripting
1

Please explain the usage of ampersand in the following command

who & echo "Total number of users are `who|wc -l`"

What I understand is that ampersand is used to run some process in the background. And, what I am expecting from this command is

"Output of who should be displayed on the screen with value of total number of users who have logged in displayed at the bottom of the list."

Thanks.

2

You are right but I guess that this is just a typo and missing a 2nd adjacent & like marked bold here:

who && echo "Total number of users are `who|wc -l`"

This works then like if the 1st who is successful, the command following will be executed, maybe to check if "who" itself is available and working. Sending "who" in the background and then following up the rest of commands would make no sense.

3

Thanks a lot. It does help.