I need to execute this command on my terminal, that will operate on a server. I need to modify it such that if I lost the connection and the terminal closes, the operation running is not stopped, continuing the operation until its conclusion.
for file in 4458*/payoffTable* ; do cp "$file" /storage/scratch2/id0056/DMM_BASTIAN/M_7/N_15_P_05/Evoluzioni;done &
I know there is a command, called "nohup", that allow that, but if I prepend it to the previous command I get an error.
Also, in the case in which some of you is able to give a solution to this problem, I would like to know how to monitor the background processes running on a remote server. Thanks for the help.
After the execution of nohup the terminal returns the PID (Process ID) that is the process identifier.
By opening a terminal and running the command
ps -ef | grep PID
the console returns your process created above, if still running. If the process is not returned, it means that the execution is completed.
Related
So how can I close the terminal where the process is in with killall.
I have tried this:
In 1st terminal:
killall node
In 2nd terminal:
Ready
Terminated
But I want only the 2nd terminal to close after the node is killed.
You can use the -t option:
killall -t $(tty)
will call all processes started from the terminal session (even with nohup), including the shell. So, your terminal will get closed.
You need to also kill the process which runs the terminal, which is usually the parent process of the node process.
The question How do I get the parent process ID of a given child process? is a good place to start. You can find the PIDs of the node processes via How to find the Process ID of a running terminal program.
I'm running some script on remote server using ssh. The task is downloading images to remote server. I'm wondering will the script keep running after I log out the ssh session? Why? Could anyone explain in detail?
If you want the script keep running after logout you need to detach it from the terminal and run it in the background:
nohup ./script.sh &
If you close the terminal where you launched a process in, the process will receive SIGHUP and unless it handles it this means the process will get terminated. HUP means hang up, like in a phone call.
The nohup command can be used to start a process and prevent it from SIGHUP signals getting send to it. An alternative would be to use the bash builtin disown, which does basically the same:
./script.sh &
disown %1
Note that the 1 represents the job id. If you running multiple processes in the background you need to specify the correct job id.
I have a bash script running on Ubuntu.
Is it possible to see the line/command executed now without script restart.
The issue is that script sometimes never exits. This is really hard to reproduce (now I caught it), so I can't just stop the script and start the debugging.
Any help would be really appreciated
P.S. Script logic is hard to understand, so I can't to figure out why it's frozen by power of thoughts.
Try to find the process id (pid) of the shell, you may use ps -ef | grep <script_name>
Let's set this pid in the shell variable $PID.
Find all the child processes of this $PID by:
ps --ppid $PID
You might find one or more (if for example it's stuck in a pipelined series of commands). Repeat this command couple of times. If it doesn't change this means the script is stuck in certain command. In this case, you may attach trace command to the running child process:
sudo strace -p $PID
This will show you what is being executed, either indefinite loop (like reading from a pipe) or waiting on some event that never happens.
In case you find ps --ppid $PID changes, this indicates that your script is advancing but it's stuck somewhere, e.g. local loop in the script. From the changing commands, it can give you a hint where in the script it's looping.
When launching a bash script in LINUX, the script succeeds and is successful, yet the terminal hangs. I must always input CTRL+C to end the program. I am able to type in the terminal and press enter, but the script does not respond.
I can not change the script files, but can I launch it so that it disables waiting for the user? Any troubleshooting tips to disable this behaviour?
You can execute the script with & at the end, this will give the control back to the shell (executes the script as a background process).
./script.sh &
If you want to stop the script, you need to get its process id and then kill it. To get the process id, either execute ps aux | grep script where script is your script name, or execute echo $! right after you launched the script. When you have the process id, you can kill the process with kill 1234 where 1234 is the process id.
If the execution time of the script can be estimated, you can kill it automatically after a certain amount of time:
bash -c '(sleep 5m; kill $$ 2> /dev/null) & exec script' &
In this command sleep 5m is the time after the process will be killed, and script is the name of your script (or the command).
For example if the script's execution time is 30 seconds on average, then you can set the timeout to a minute or two to give it some extra time in case the execution is slower than usual. Note that this command doesn't guarantee that the script finished its execution, so use it with care.
Well, I'm basically trying to make a bash script runs a node script forever. I made the following bash script:
#!/bin/bash
while true ; do
cd /myscope/
unlink nohup.out
node myscript.js
sleep 6
done & echo $! > pid
I'm expecting that when it runs, it starts up node with the given script, checks if node exits, sleeps for 6 seconds if so and reopen node. Also, I'm expecting it to run in background and writes it's pid (the bash pid) on a file called "pid".
Everything explained above works as expected, apparently, but I'm also expecting that when the pid of the bash script is killed, the node script would stop running, I don't know why that made sense in my mind, but when it comes to practice, it doesn't work. The bash script is killed indeed, but the node script keeps running and that is freaking me out.
I've tested it in the terminal, by not sending the bash script to the background and entering ctrl+c, both scripts gets killed.
I'm obviously miss understanding something on the way the background process works. For god sake, can anybody help me?
There are lots of tools that let you do what you're trying, just two off the top of my head:
https://github.com/nodejitsu/forever - A simple CLI tool for ensuring that a given script runs continuously (i.e. forever)
https://github.com/remy/nodemon - Monitor for any changes in your node.js application and automatically restart the server - perfect for development
Maybe the second it's not what you're looking for, but still worth a look.
If you can't or don't want to use those then the problem is that if you kill the parent process the child one is still there, so, you should kill that too:
pkill -TERM -P $PID
where $PID is the parent PID.