https://unix.stackexchange.com/questions/104821/how-to-terminate-a-background-process
There are many ways to go about this.
Method #1 - ps
You can use the ps command to find the process ID for this process and then use the PID to kill the process.
Example
$ ps -eaf | grep [w]get
saml 1713 1709 0 Dec10 pts/0 00:00:00 wget ...
$ kill 1713
Method #2 - pgrep
You can also find the process ID using pgrep.
Example
$ pgrep wget
1234
$ kill 1234
Method #3 - pkill
If you're sure it's the only wget you've run you can use the command pkill to kill the job by name.
Example
$ pkill wget
Method #4 - jobs
If you're in the same shell from where you ran the job that's now backgrounded. You can check if it's running still using the jobs command, and also kill it by its job number.
Example
My fake job, sleep.
$ sleep 100 &
[1] 4542
Find it's job number. NOTE: the number 4542 is the process ID.
$ jobs
[1]+ Running sleep 100 &
$ kill %1
[1]+ Terminated sleep 100
Method #5 - fg
You can bring a backgrounded job back to the foreground using the fg command.
Example
Fake job, sleep.
$ sleep 100 &
[1] 4650
Get the job's number.
$ jobs
[1]+ Running sleep 100 &
Bring job #1 back to the foreground, and then use Ctrl+C.
$ fg 1
sleep 100
^C
$