IN ubuntu Amazon EC2 instances with root access
when do
ps -e
The process shows up with a valid PID and process name. The database table also suggests the process is still ongoing.
PID TTY TIME CMD
32194 ? 00:00:00 test
32253 ? 00:00:00 mysql
However, any of the following commands kill the process, but returns nothing or "invalid signal".
top
kill
Type in PID
y
returns "invalid signal"
or
kill -9 PID
kill -s PID
etc.
Could any guru enlighten how to deal with the "ghost jobs"?
Did you use the correct rights to kill the process? With root you should be able to kill the process using either:
$ su -
# kill -9 PID
or
$ sudo kill -9 PID
You have the id of the process, say 32194, I suggest you run:
pgrep -l a | grep 32194
If the process name has an 'a', the output will show the line and the process name. if not have an 'a', change the letter by other one.
When the process appear, just kill it with:
pkill <process name>
My unix production server has test.ksh files, but every day it's running on daily basics using job.
I want to know which crontab job is calling this script. I checked usign below command, but i didn't find exact job name,
crontab -l
--It has been listed 100 job --
I have analysed above mentioned 100 job, but i didn't get test.ksh file
crontab -l | grep "test.ksh"
--file not found
But the file available in one directory, I can't find which job is called test.ksh script.
Finding:
1. Whether it's child job? - If yes, how can i identify the child job?
you could use pstree -p xxxx where xxxx is the pid of crond. You will then get a nice hierarchical overview of all offspring processes of crond.
If it is a child script, use ps -ef and use the ppid of the test.ksh job to identify the calling script.
For example, consider these two scripts, the first just calls the second
parent
#! /bin/sh
# Run child process
./child
child
#! /bin/sh
sleep 60
ps -ef shows (with a lot of other processes removed)
UID PID PPID C STIME TTY TIME CMD
501 5725 5724 0 8:22pm ttys000 0:00.28 -bash
501 6046 5725 0 11:38am ttys000 0:00.01 /bin/sh ./parent
501 6047 6046 0 11:38am ttys000 0:00.00 /bin/sh ./child
501 6048 6047 0 11:38am ttys000 0:00.00 sleep 60
The pid is the process identifier, so child has process id 6047. Its ppid - 6046 - is the process id of its parent as you can see looking at the entry for the parent process.
How can I monitor a job that is still running (I guess detached?) after I started it with nohup, exited the server and logged back in? Normally, I use jobs -l to see what's running, but this is showing blank.
You need to understand the difference between a process and a job. Jobs are managed by the shell, so when you end your terminal session and start a new one, you are now in a new instance of Bash with its own jobs table. You can't access jobs from the original shell but as the other answers have noted, you can still find and manipulate the processes that were started. For example:
$ nohup sleep 60 &
[1] 27767
# Our job is in the jobs table
$ jobs
[1]+ Running nohup sleep 60 &
# And this is the process we started
$ ps -p 27767
PID TTY TIME CMD
27767 pts/1 00:00:00 sleep
$ exit # and start a new session
# Now jobs returns nothing because the jobs table is empty
$ jobs
# But our process is still alive and kicking...
$ ps -p 27767
PID TTY TIME CMD
27767 pts/1 00:00:00 sleep
# Until we decide to kill it
$ kill 27767
# Now the process is gone
$ ps -p 27767
PID TTY TIME CMD
You can monitor if the proceses if still running using
ps -p <pid>, where is the ID of the process you get after using the nohup command.
If you see valid entries you process is probably alive.
You could have a list of the processes running under current user with ps -u "$USER" or ps -u "$(whoami)".
Try this :
ps -ef | grep <pid>
I'm running a nohup process on the server. When I try to kill it my putty console closes instead.
this is how I try to find the process ID:
ps -ef |grep nohup
this is the command to kill
kill -9 1787 787
When using nohup and you put the task in the background, the background operator (&) will give you the PID at the command prompt. If your plan is to manually manage the process, you can save that PID and use it later to kill the process if needed, via kill PID or kill -9 PID (if you need to force kill). Alternatively, you can find the PID later on by ps -ef | grep "command name" and locate the PID from there. Note that nohup keyword/command itself does not appear in the ps output for the command in question.
If you use a script, you could do something like this in the script:
nohup my_command > my.log 2>&1 &
echo $! > save_pid.txt
This will run my_command saving all output into my.log (in a script, $! represents the PID of the last process executed). The 2 is the file descriptor for standard error (stderr) and 2>&1 tells the shell to route standard error output to the standard output (file descriptor 1). It requires &1 so that the shell knows it's a file descriptor in that context instead of just a file named 1. The 2>&1 is needed to capture any error messages that normally are written to standard error into our my.log file (which is coming from standard output). See I/O Redirection for more details on handling I/O redirection with the shell.
If the command sends output on a regular basis, you can check the output occasionally with tail my.log, or if you want to follow it "live" you can use tail -f my.log. Finally, if you need to kill the process, you can do it via:
kill -9 `cat save_pid.txt`
rm save_pid.txt
I am using red hat linux on a VPS server (and via SSH - putty), for me the following worked:
First, you list all the running processes:
ps -ef
Then in the first column you find your user name; I found it the following three times:
One was the SSH connection
The second was an FTP connection
The last one was the nohup process
Then in the second column you can find the PID of the nohup process and you only type:
kill PID
(replacing the PID with the nohup process's PID of course)
And that is it!
I hope this answer will be useful for someone I'm also very new to bash and SSH, but found 95% of the knowledge I need here :)
suppose i am running ruby script in the background with below command
nohup ruby script.rb &
then i can get the pid of above background process by specifying command name. In my case command is ruby.
ps -ef | grep ruby
output
ubuntu 25938 25742 0 05:16 pts/0 00:00:00 ruby test.rb
Now you can easily kill the process by using kill command
kill 25938
jobs -l should give you the pid for the list of nohup processes.
kill (-9) them gently.
;)
You could try
kill -9 `pgrep [command name]`
Suppose you are executing a java program with nohup you can get java process id by
`ps aux | grep java`
output
xxxxx 9643 0.0 0.0 14232 968 pts/2
then you can kill the process by typing
sudo kill 9643
or lets say that you need to kill all the java processes then just use
sudo killall java
this command kills all the java processes. you can use this with process. just give the process name at the end of the command
sudo killall {processName}
If your application always uses the same port, you can kill all the processes in that port like this.
kill -9 $(lsof -t -i:8080)
This works in Ubuntu
Type this to find out the PID
ps aux | grep java
All the running process regarding to java will be shown
In my case is
johnjoe 3315 9.1 4.0 1465240 335728 ? Sl 09:42 3:19 java -jar batch.jar
Now kill it kill -9 3315
The zombie process finally stopped.
when you create a job in nohup it will tell you the process ID !
nohup sh test.sh &
the output will show you the process ID like
25013
you can kill it then :
kill 25013
I started django server with the following command.
nohup manage.py runserver <localhost:port>
This works on CentOS:
:~ ns$netstat -ntlp
:~ ns$kill -9 PID
This works for mi fine on mac
kill -9 `ps -ef | awk '/nohup/{ print \$2 }'`
I often do this way. Try this way :
ps aux | grep script_Name
Here, script_Name could be any script/file run by nohup.
This command gets you a process ID. Then use this command below to kill the script running on nohup.
kill -9 1787 787
Here, 1787 and 787 are Process ID as mentioned in the question as an example.
This should do what was intended in the question.
If you are unaware of the PID, then first find it using TOP command
top -U userid
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
You will get the PID using top, then perform the kill operation.
$ kill -9 <PID>
Today I met the same problem. And since it was a long time ago, I totally forgot which command I used and when. I tried three methods:
Using the STIME shown in ps -ef command. This shows the time you start your process, and it's very likely that you nohup you command just before you close ssh(depends on you) . Unfortunately I don't think the latest command is the command I run using nohup, so this doesn't work for me.
Second is the PPID, also shown in ps -ef command. It means Parent Process ID, the ID of process that creates the process. The ppid is 1 in ubuntu for process that using nohup to run. Then you can use ps --ppid "1" to get the list, and check TIME(the total CPU time your process use) or CMD to find the process's PID.
Use lsof -i:port if the process occupy some ports, and you will get the command. Then just like the answer above, use ps -ef | grep command and you will get the PID.
Once you find the PID of the process, then can use kill pid to terminal the process.
About losing your putty: often the ps ... | awk/grep/perl/... process gets matched, too! So the old school trick is like this
ps -ef | grep -i [n]ohup
That way the regex search doesn't match the regex search process!
if you are on a remote server, check memory usage with top , and find your process and its ID. After that, just execute kill [your process ID] .
There are various tricks to daemonize a linux process, i.e. to make a command running after the terminal is closed.
nohup is used for this purpose, and fork()/setsid() combination can be used in a C program to make itself a daemon process.
The above was my knowledge about linux daemon, but today I noticed that exiting the terminal doesn't really terminate processes started with & at the end of the command.
$ while :; do echo "hi" >> temp.log ; done &
[1] 11108
$ ps -ef | grep 11108
username 11108 11076 83 15:25 pts/0 00:00:05 /bin/sh
username 11116 11076 0 15:25 pts/0 00:00:00 grep 11108
$ exit
(after reconnecting)
$ ps -ef | grep 11108
username 11108 1 91 15:25 pts/0 00:00:17 /bin/sh
username 11130 11540 0 15:25 pts/0 00:00:00 grep 11108
So apparently, the process's PPID changed to 1, meaning that it got daemonized somehow.
This contradicts my knowledge, that & is not enough and one must use nohup or some other tricks to a process 'daemon'.
Does anyone know who is doing this daemonizing?
I'm using a CentOS 6.3 host and putty/cygwin/sshclient produced the same result.
You can daemonize a process if that doesn't respond to SIGHUP signal.
When bash shell is terminated while it is running background tasks, bash shell sends SIGHUP
(hangup signal) to all tasks. However bash won't wait until child processes are completely
terminated. If child process doesn't respond to SIGHUP signal, that process becomes an orphan
process. (its parent pid is changed to 1 - init process - to prevent becoming a useless zombie process)
Subshell executions basically do not responds to SIGHUP signals, thus your command will still be running after logging out from the first shell.