Script which executes commands in infinite loop in background
<SOMETHING ELSE AT START OF SCRIPT>
cmd='while true;
do
ps aux | head;
sleep 1;
done > $FILE'
ssh root#$SERVER $cmd &
...
...
<SOME OTHER TASKS>
...
...
( at the end of this script, how to kill the above snippet executing in remote server)
[ kindly note i dont want to wait as the while loop is infinite ]
Read and tried some posts from stackoverflow, but could not find exact solution for this problem.
Rather than an infinite loop, use a sentinel file:
cmd='while [ -r /tmp/somefile];
do
# stuff
done > $FILE'
ssh root#$SERVER touch /tmp/somefile
ssh root#$SERVER $cmd &
# do other stuff
ssh root#$SERVER rm -f /tmp/somefile
This follows your current practice of putting the remote command in a variable, but the arguments against that cited elsewhere should be considered.
If you want to kill the ssh process running in background at the end of your script, just do:
kill $!
I assume this is the only (or the last) process you started in background.
Try following sequence
CTRL+Z
fg
CTRL+C
or
jobs
kill %jobspec
To kill everything belonging to user logged in you could try:
whois=`w|grep $user|awk '{print $2}'`;user=root; ssh $user#server -C "ps auwx|grep $whois|awk '{print \$2}'"
This will list all the processes owned by the user you just logged in as - just add |xargs kill -9
whois=`w|grep $user|awk '{print $2}'`;user=root; ssh $user#server -C "ps auwx|grep $whois|awk '{print \$2}'|xargs kill -9 "
whois=`w|grep $user|awk '{print $2}'`;user=root; ssh $user#server -C "ps auwx|grep $whois|awk '{print \$2}'|awk '{print "kill -9 " $1}'|/bin/sh "
Related
I run the this command
$(while true;do echo Something && sleep 0.01; done;) | cat
Now I can not exit by Ctrl+C or background it by Ctrl+Z, and ps aux can't tell me which bash it is.How can I quit that bash ?
EDIT
I narrow donw the pid by find the cwd pgrep bash| (while read -r line; do lsof -p $line|grep cwd|grep EXPECTED_CWD && echo "GOT $line"; done;),finally kill that process.There is easier way to find that, but no /proc on mac.
Closing the terminal can help.
If you are using CLI-only os then you can switch to different terminal using Ctrl + Alt + F1 keys.
There you can use who or ps commands to get process-id and kill it.
ps -ef will list all processes.
you can kill second last bash process, as that will be the last command that you executed.
Note : process id assignment in linux is always greater than old one.
you're able to execute your commands with & symbol in the end of the command to run this command in background
In your case command looks like:
$(while true;do echo Something && sleep 0.01; done;) | cat &
It will show the process ID, and you'll be able to kill it, when you want
I need to start a program, which uses a serial port from within a bash script. The matter is that prior to doing that I need to kill "-sh" process in order to release the serial port occupied by it (I use a serial console and this is the only way to communicate with Linux). When I kill "-sh" my program doesn't start, however the bash script continues to execute. If I don't kill "-sh" my program normally starts. See code below for details:
#!/bin/bash
SH_PID=`ps -o comm,pid | egrep -e '^sh' | awk -F " " '{print $2}'`
kill -9 $SH_PID
myprog #start my program
while true
do
sleep 10
echo "script is running..." > /dev/ttyS0
done
Any thoughts?
What if you kill your shell after running your program in background:
#!/bin/bash
SH_PID=`ps -o comm,pid | egrep -e '^sh' | awk -F " " '{print $2}'`
nohup myprog & #start my program in background
kill --HUP $SH_PID
while true
do
sleep 10
echo "script is running..." > /dev/ttyS0
done
I have a script that has to kill a certain number of times a resource managed by a high avialability middelware. It basically checks whether the resource is running and kills it afterwards, i need the timestamp of when the proc is really killed. So i have done this code:
#!/bin/bash
echo "$(date +"%T,%N") :New measures Run" > /home/hassan/logs/measures.log
for i in {1..50}
do
echo "Iteration: $i"
PID=`ps -ef | grep "/home/hassan/Desktop/pcmAppBin pacemaker_app/MainController"|grep -v "grep" | awk {'print$2'}`
if [ -n "$PID" ]; then
echo "$(date +"%T,%N") :Killing $PID" >> /home/hassan/logs/measures.log
ps -ef | grep "/home/hassan/Desktop/pcmAppBin pacemaker_app/MainController"|grep -v "grep" | awk {'print "kill -9 " $2'} | sh
wait $PID
else
PID=`ps -ef | grep "/home/hassan/Desktop/pcmAppBin pacemaker_app/MainController"|grep -v "grep" | awk {'print$2'}`
until [ -n "$PID" ]; do
sleep 2
PID=`ps -ef | grep "/home/hassan/Desktop/pcmAppBin pacemaker_app/MainController"|grep -v "grep" | awk {'print$2'}`
done
fi
done
But with my wait command i get the following error message: wait: pid xxxx is not a child of this shell
I assume that You started the child processes from bash and then start this script to wait for. The problem is that the child processes are not the children of the bash running the script, but the children of its parent!
If You want to launch a script inside the the current bash You should start with ..
An example. You start a vim and then You make is stop pressing ^Z (later you can use fg to get back to vim). Then You can get the list of jobs by using the˙jobs command.
$ jobs
[1]+ Stopped vim myfile
Then You can create a script called test.sh containing just one command, called jobs. Add execute right (e.g. chmod 700 test.sh), then start it:
$ cat test.sh
jobs
~/dev/fi [3:1]$ ./test.sh
~/dev/fi [3:1]$ . ./test.sh
[1]+ Stopped vim myfile
As the first version creates a new bash session no jobs are listed. But using . the script runs in the present bash script having exactly one chold process (namely vim). So launch the script above using the . so no child bash will be created.
Be aware that defining any variables or changing directory (and a lot more) will affect to your environment! E.g. PID will be visible by the calling bash!
Comments:
Do not use ...|grep ...|grep -v ... |awk --- pipe snakes! Use ...|awk... instead!
In most Linux-es you can use something like this ps -o pid= -C pcmAppBin to get just the pid, so the complete pipe can be avoided.
To call an external program from awk you could try system("mycmd"); built-in
I hope this helps a bit!
Here is my script.sh
for ((i=1; i<=400000; i++))
do
echo "loop $i"
echo
numberps=`ps -ef | grep php | wc -l`;
echo $numberps
if [ $numberps -lt 110 ]
then
php5 script.php &
sleep 0.25
else
echo too much process
sleep 0.5
fi
done
When I launch it with:
./script.sh > /dev/null 2>/dev/null &
that works except when I logout from SSH and login again, I cannot stop the script with kill%1 and jobs -l is empty
When I try to launch it with
nohup ./script.sh &
It just ouputs
nohup: ignoring input and appending output to `nohup.out'
but no php5 are running: nohup has no effect at all
I have 2 aleternatives to solve my problem:
1) ./script.sh > /dev/null 2>/dev/null &
If I logout from SSH and login again, How can I delete this job ?
or
2) How to make nohup run correctly ?
Any idea ?
nohup is not supposed to allow you to use jobs -l or kill %1 to kill jobs after logging out and in again.
Instead, you can
Run the script in the foreground in a GNU Screen or tmux session, which lets you log out, log in, reattach and continue the same session.
killall script.sh to kill all running instances of script.sh running on the server.
When I do the following, then I have to press CTRL-c afterwards or the shell acts weird. Left/right arrows keys e.g. doesn't move correctly and the text is messed up.
# read -r pid < <(ssh 10.10.10.46 'sleep 50 & echo $!') ; echo $pid
2135
# Killed by signal 2.
^C
#
I need this for a script, so I'd like to know why CTRL-c is needed and is it possible to work around it?
Update
It looks like it opens an extra Bash shell, and that is the one that needs to be exited.
The command I am actually interesting in is
read -r pid < <(ssh 10.10.10.46 "mbuffer -4 -v 0 -q -I 8023 > /tmp/mtest & echo $!"); echo $pid
Try this instead:
read -r pid \
< <(ssh 10.10.10.46 'nohup mbuffer >/tmp/mtest </dev/null 2>/tmp/mtest.err & echo $!')
Three important changes:
Use of nohup (you could also get a similar effect with the bash built-in disown)
Redirection of stdin and stderr to files (preventing them from holding handles that connect, eventually, to your terminal).
Use of single quotes for the remote command (with double-quotes, expansions happen before ssh is started, so the $! you get is the PID of the most recently started local background process).