I have started a wget on remote machine in background using &. Suddenly it stops downloading. I want to terminate its process, then re-run the command. How can I terminate it?
I haven't closed its shell window. But as you know it doesn't stop using Ctrl+C and Ctrl+Z.
There are many ways to go about this.
You can use the ps command to find the process ID for this process and then use the PID to kill the process.
$ ps -eaf | grep [w]get
saml 1713 1709 0 Dec10 pts/0 00:00:00 wget ...
$ kill 1713
You can also find the process ID using pgrep.
$ pgrep wget
1234
$ kill 1234
If you're sure it's the only wget you've run you can use the command pkill to kill the job by name.
$ pkill wget
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.
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
You can bring a backgrounded job back to the foreground using the fg command.
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
$
ps. The 3rd # is the parent's process id.
ps -eaef| grep [w]get.
ps -eaf | grep [w]get. The options are are in the ps man page. man ps.
kill %% kills the last background process. Repeating it will kill the one before and so on. kill %1 kills the first background process.
Commented
Feb 5, 2020 at 12:06
grep into not showing the actual grep command in the output. The grep command shows up as grep [w]get but the command grep is looking for the string wget. The [...] is a set of characters, in this case a set of 1 character, w.
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)
kill -9 %6 is the correct command that will remove the job number 6. Number 9 indicates type of the signal that kill command sends.
kill %{1,2,3,4} (should work in bash/zsh).
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.
It's an old question and there are already few good answers, but, I'll try to present mine in a little different way.
Actually, backgrounded processes are called jobs, and job control is very well explained in those 3 short pages: https://www.gnu.org/software/bash/manual/html_node/Job-Control.html
Basically, we can reference a job by a jobspec, that is the symbol % follow either by another symbol (or a sequence in some fancier cases), or by a job ID. And it's the same for kill, fg, bg or disown.
%+ (or just %, or %%) will reference the latest backgrounded
job (current)%- will reference the previous one%{jobid} will reference the specified jobTo list your backgrounded jobs, you use the command jobs.
kill $! has a different behavior, it will kill the latest process sent in the background as a job, and not the latest job created.
You have sent 5 jobs in the background.
You bring back job #2 in the foreground (fg %2, or just %2), then sent it back in the background (<Ctrl-Z>, then bg).
It is the latest process sent to the background, but it remains job #2.
So that kill $! will terminate job #2 - the latest process (re)sent to the background, while kill %+ will kill job #5, the latest job that have been created ("current job"):
$ jobs [1] Running sleep 1000 & [2] Running sleep 2000 & [3] Running sleep 3000 & [4]- Running sleep 4000 & [5]+ Running sleep 5000 & $ fg %2 sleep 2000 ^Z [2]+ Stopped sleep 2000 $ bg [2]+ sleep 2000 & $ jobs [1] Running sleep 1000 & [2] Running sleep 2000 & [3] Running sleep 3000 & [4]- Running sleep 4000 & [5]+ Running sleep 5000 & $ kill %+ $ jobs [1] Running sleep 1000 & [2] Running sleep 2000 & [3] Running sleep 3000 & [4]- Running sleep 4000 & [5]+ Terminated sleep 5000 $ kill $! [2] Terminated sleep 2000 $ jobs [1] Running sleep 1000 & [3]- Running sleep 3000 & [4]+ Running sleep 4000 &
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.
in bash last stopped process (Ctrl-Z) you will kill by:
kill %%
kill -9 %%
or if want to choose, use:
jobs
then:
kill %N
like kill %2
%% always refer to the most recent background job?
Commented
Jan 4 at 13:32
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
The Easiest way is to use -9 flag on kill command
user@host:/path> jobs
[1]+ Running /usr/home/script1.sh $i &
user@host:/path> fg
/usr/home/script1.sh $i
^C
[1]+ Stopped /usr/home/script1.sh $i
user@host:/path> kill -9 %1
[1]+ Stopped /usr/home/script1.sh $i
user@host:/path>
[1]+ Killed /usr/home/script1.sh $i
user@host:/path>
user@host:/path> jobs
user@host:/path>
A common example is the stress tool. Let say you ran the following:
$ stress -c 4 -m 4
and closed the terminal window. The process would continue eating your resources from the background.
Hers’s what I do:
$ x=`pgrep stress` ; sudo kill -9 $x
pgrep lists the PIDs of the subjected process and stores it into variable x which then used by kill -9 to terminate it.
List All Jobs by typing
jobs
Output>>[1]+ Stopped sudo nano ls.txt
Take this process to foreground and kill
fg %1
then press ctrl+c
kill %1 (as suggested by others) will, but Ctrl+C is meaningless against programs that ignore the keyboard interrupt as mentioned in this question
I am lazy and I got bit tired googling what incantation of ctrl % signal number fg bg jobs disown and god knows what else to use for something which should be trvial.
I recommend looking around for cli alternatives to commonly used commands in general as productivity boost as for anything to do with running processes I can't recommend btop enough I won't tell you how to use it because its actually made to be used by humans.
I bet its available via package manager of your choice give it a shot you won't look back there is also very nice procs.
