mjhjmtu

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
$

In bash you can use fg to get the job to the foreground and then use Ctrl+C

Or list the process in the background with jobs and then do

kill %1

(with 1 replaced by the number jobs gave you)

You can equally use kill $! to kill the most recently backgrounded job.

EDIT: Once in the foreground, you can Ctrl+C, or as @Zelda mentions, kill with the '%x' where 'x' is the job number will send the default signal (most likely SIGTERM in the case of Linux).

just type fg to bring it to the foreground, if it was the last process you backgrounded (with '&').

If it was not the last one, type: jobs and find the 'job number', represented in ''. Then just type:

fg 2

..where '2' is the job number, for example:

foo@bar:~/junk/books$ jobs
[1]+ Running okular how_to_cook_a_turkey.pdf &
foo@bar:~/junk/books$ fg 1
okular how_to_cook_a_turkey.pdf <- this is now in the foreground.

The correct way is to type jobs then use the job number to kill it. In order to use the pid to kill it you need to bring it to the foreground as noted in the first answer.

Try this

~/Desktop$ sleep 1000 &
[1] 7056

~/Desktop$ jobs

[1]+ Running sleep 1000 &

/Desktop$ kill %1 #(%1 is the job number)

If you run jobs right after you kill it you should see this

Desktop$ jobs
[1]+ Terminated sleep 1000

One thing I don't see here, which I've found very useful especially when testing out commands, is pidof. You can use pidof [command] to find the process id of a process that is currently running. I like it because it allows me to quickly find the id of the command I want, which is usually something I just invoked.

Once you have the pid, you can simply kill the process. It allows for creating simple scripts for killing a process only if it's currently running.