Questions about the various ways jobs can be controlled by the shell: suspending, resuming, terminating execution etc.

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35
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2answers
29k views

How to suspend and resume processes

In the bash terminal I can hit Control+Z to suspend any running process... then I can type fg to resume the process. Is it possible to suspend a process if I only have it's PID? And if so, what ...
234
votes
2answers
63k views

Difference between nohup, disown and &

What is the difference between $ nohup foo and $ foo & and $ foo & $ disown
13
votes
5answers
10k views

How can I kill and wait for background processes to finish in a shell script when I Ctrl+C it?

I'm trying to set up a shell script so that it runs background processes, and when I Ctrlc the shell script, it kills the children, then exits. The best that I've managed to come up with is this. It ...
3
votes
4answers
663 views

How can I turn the behavior of `gedit something & disown` into the default behavior when calling gedit from the command line?

When I gedit files from the command line, it's always locking the terminal, and I'm tired of explicitly commanding a detached process for it. I tried to alias gedit as something like gedit $* & ...
4
votes
1answer
67 views

Why is subshell created by background control operator (&) not displayed under pstree

I understand that when I run exit it terminates my current shell because exit command run in the same shell. I also understand that when I run exit & then original shell will not terminate because ...
6
votes
1answer
10k views

How to recover a backgrounded job from a previous shell? [duplicate]

Possible Duplicate: How can I disown a running process and associate it to a new screen shell? I launched a command that lasts a long time. I had to disconnect so I moved it in the ...
5
votes
1answer
950 views

Change the parent process of a process?

Is it possible to change the parent process of a process? If yes, how? For example, how does screen manage to attach a screen session and the processes running inside it to different shell ...
20
votes
4answers
5k views

What happens to the output of a process that has been disowned and lost its terminal?

If I close the virtual terminal, where some process was started, does the output just go straight to /dev/null, or can it pollute memory somehow? Can I anyhow grab the output to continue reading it at ...
0
votes
0answers
35 views

How to check if process completed successfully or if there are any errors?

MYPROGRAM > output.out 2> output.err The two files will be generated: output.err and output.out. Surely after a job is completed its process ID no longer exists, but how can I check if it ...
109
votes
8answers
55k views

How can I disown a running process and associate it to a new screen shell?

I have a running program on a SSH shell. I want to pause it and be able to unpause its execution when I come back. One way I thought of doing that was to transfer its ownership to a screen shell, ...
7
votes
4answers
1k views

Get PID of any command in backgrounded piped sequence of commands

If, in bash, I execute: cmd1 | cmd2 | ... | cmdi | ... | cmdn & where the cmd{1..n} may not be distinct, how do I get the PID of cmdi? Alternatively, how can I signal the cmdi process? (For ...
7
votes
2answers
502 views

Ctrl-C kills whole line while Ctrl-Z doesn't

I am running multiple commands on the command line separated using semi-colons: cmd1; cmd2; cmd3 If I press ctrl-c on the above, it would kill all commands instead of just the one which is executing ...
1
vote
2answers
29 views

How to control a backgrounded subshell?

If I run the following command at a bash prompt: (for i in {1..100}; do echo $i; sleep 1; done) & It will start counting and immediately return me to my prompt. I can continue working normally, ...
1
vote
2answers
161 views

Result of combination of Ctrl+c and then Ctrl+z in shell

Which signal will be sent to the running process after sending the Ctrlc after 500ms of Ctrlz? I have tried to give the Ctrlc after Ctrlz but I didn't get the exact answers for this.
0
votes
2answers
37 views

How to resume a program when logged in with different session

Here is the scenario: Let's say that I log into my server via ssh and start an emacs or vi (or whatever other program) session. Then my ssh connection disconnects. Is there a way for me to reconnect ...
1
vote
3answers
24k views

How to get the Job ID? [duplicate]

As we know, the shell enables the user to run background processes using & at the command line's end. Each background process is identified by a job ID and, of course, by it's PID. When I'm ...
1
vote
2answers
104 views

Job control over a Bash script

I have a Bash script of a thousand lines each containing an ffmpeg command. I start this with source script and it runs just fine. However, when I try to take control of this script in various ways, ...
6
votes
1answer
13k views

ctrl c vs. ctrl z with foreground job

Ctrl+Z stops the job whereas Ctrl+C kills the job. Why is that? Wouldn't the other way make more sense? z@z-lap:~$ sleep 100& [1] 4458 z@z-lap:~$ sleep 200& [2] 4459 z@z-lap:~$ jobs [1]- ...
2
votes
3answers
100 views

Preventing terminal disconnection from killing a running job in zsh [duplicate]

I went through the top answer to this question: Difference between nohup, disown and &, and I read specfically the following: With disown the job is still connected to the terminal, so if the ...
0
votes
2answers
92 views

Live monitoring of background jobs

I executed a command like this: nohup some_command &. Now this command is in the background. I can see it with the command jobs. Example output: [1]+ Running nohup some_command ...
2
votes
2answers
772 views

Queue a task in a running shell

I often start a long running command that is bound to either CPU, Disk, RAM or Internet connection. While that is running, I find that I want to run a similar command. Let's say downloading something ...
2
votes
2answers
110 views

How do I kill a process after detaching it from bash?

I have multiple scripts that detach a process from bash using nohup and &>/dev/null &. My question is, how do I kill the process after completely detaching it from bash. using killall or ...
7
votes
4answers
1k views

Why doesn't SIGKILL terminate a stopped program (yes)?

I'm using Ubuntu 14.04 and I'm experiencing this behavior I can't seem to understand: Run the yes command (in the default shell: Bash) Type CtrlZ to stop yes Run jobs. Output: [1]+ Stopped yes ...
2
votes
1answer
110 views

Force a job to come in foreground when asked for user input

I'm currently working on an audit-script for a huge platform. In the main-script we use traps and in one of the traps I ask the user for clean up the files. The script has no output in standard ...
2
votes
2answers
173 views

Linux stop background process via kill + PID

Here http://unix.stackexchange.com/a/104825/109539 man says that to stop background process kill + PID must be used. However I can't stop background process using kill +PID, only kill + JOB ID ...
5
votes
1answer
479 views

Can someone explain in detail what “set -m” does?

On the man page, it just says: -m Job control is enabled. But what does this actually mean? I came across this command in a SO question, I have the same problem as OP, which is "fabric cannot ...
1
vote
1answer
727 views

redirecting output of running background job in bash

in bash I have some jobs running, in background. They are always producing random irrelevant error messages that pollute the terminal. I am not always so prompt to start them with the 2>&1 > ...
3
votes
1answer
322 views

Minus and Plus Sign in jobs Process

These commands are running in the background: foo@contoso ~ $ sleep 30 & foo@contoso ~ $ sleep 60 & foo@contoso ~ $ sleep 90 & What is the minus and plus sign after running jobs process? ...
2
votes
0answers
110 views

A way to distinguish between interleaved output from two background processes

If I have two backgrounded processes that produce input to STDOUT or STDERR (e.g., two installation scripts), is there an easy way to make these two output streams distinguishable? I guess I can pipe ...
58
votes
4answers
101k views

How to suspend and bring a background process to foreground

I have a process originally running in the foreground. I suspended by Ctrl+Z, and then resume its running in the background by bg <jobid>. I wonder how to suspend a process running in the ...
2
votes
1answer
58 views

Pipelines, Jobs and Processes in Zsh

I went through the Jobs & Signals documentation in Zsh, but some things aren't still clear to me. It says: If the MONITOR option is set, an interactive shell associates a job with each ...
5
votes
4answers
2k views

When I run `./command.sh &` the background task is suspended. How can I keep it running?

This is what I'm running: alexandma@ALEXANDMA-1-MBP ./command.sh & [2] 30374 alexandma@ALEXANDMA-1-MBP [2] + suspended (tty output) ./command.sh I don't want it suspended to start, I want it ...
2
votes
3answers
203 views

Running a timed background job in bash

I would like to execute a command in bash every 30 seconds and have it run as a background job. Form this post, I gather that using the watch command is useful. However every time I attempt to ...
1
vote
1answer
39 views

Replacement queue now that batch doesn't accept input files?

Background I work at a research institute, and have for a long time used the batch command to submit job queues to our machines. However, a recent update changed the batch command to be ...
1
vote
1answer
3k views

Start a background process from a script and manage it when the script ends

I'd like to run and configure a process similarly to a daemon from a script. My shell is zsh emulated under Cygwin and the daemon is SFK, a basic FTP server. For what matters here, the script ...
1
vote
1answer
450 views

Running commands after ampersand symbol & in a remote ssh session

I have a shell script that initiates a long, resource-intensive command on several different machines. In order to execute the script on each machine in parallel, I have an ampersand symbol after ...
1
vote
1answer
43 views

Run program while computer is cool

I'm trying to compile a program on a computer with inadequate cooling. The program, specifically, is the linux-ck kernel with -mtune=native march=native processor-specific optimizations, so simply ...
0
votes
2answers
319 views

How to know when a job in screen finishes?

Is it possible to know if a script executed inside a screen session finished or not? The script can be seen by typing jobs and I would like to terminate the screen session when the script is finished. ...
3
votes
2answers
459 views

What would stop a task from being run in the background?

I have a script I'm trying to launch with php ./Script.php & The task goes into the background but it is stopped. When I try to run it with bg it simply stays stopped. $ jobs [1]+ Stopped ...
5
votes
4answers
2k views

disabling job control in bash (CTRL-Z)

It happens to me sometimes, that I press CTRL+Z by accident and my application disappears into background. I know, I can bring it back with fg, so it's not such a big deal. But I am wondering about ...
0
votes
0answers
17 views

How to cancel my job [duplicate]

I'm a beginner about LINUX in korea and English is too. I'm circulating some simulation by using the LINUX cluster but I have some problem in my job. I want to cancel any job (ID : 750, 752, 753 ...
0
votes
1answer
27 views

Starting up and keeping up a process

I am having an Ubuntu box on which I am having a Haskell process (think of it as a random server process) that I built. I want to start it on boot and restart it in case it fails for whatever reason ...
0
votes
1answer
79 views

How to dynamically chose PBS queue during job submission

I run a lot of small computing jobs in remote cluster where job submission is managed by PBS. Normally in a PBS (bash) script I specify the queue that I would like to submit the job through the ...
10
votes
1answer
9k views

How to suspend and resume processes like bash does

this question is a follow-up to: How to suspend and resume processes I have started firefox from a bash session in gnome-terminal. The process tree looks like this: $ ps -e -o pid,ppid,cmd -H 1828 ...
1
vote
1answer
181 views

Submitting jobs with sequential completion

If I have numerous jobs that rely on environment variables, how can I submit them sequentially? Here is my attempt that has not been working, week 6 is always submitted (and finishes) before week 5. ...
0
votes
2answers
231 views

UNIX: Submit job only after previous job completes?

I would like to submit the same .sas job iterating over an argument, but I would like job only to be submitted after the previous is completed. Here is my attempt: #!/bin/ksh export weeks="1 ...
4
votes
5answers
4k views

Run a process to particular/dedicated pid only

I have a c program executable or shell script which I want to run very often. If I want to stop/pause or to notify something I will send signal to that process. So every time I have to check the pid ...
2
votes
1answer
257 views

mpd daemon prematurely ending jobs

I am a little out of my depth here so bear with me. I am trying to configure mpirun and mpiexec to run software called Materials Studio on a 1 node, 2 processor, 12 core cluster. The submission scheme ...
1
vote
0answers
119 views

Why doesn't putting elinks in background and then resuming with `fg` work reliably?

The elinks program takes over the terminal to let you browse the web. But its behavior in the context of job control is wonky. If I CTRL-Z suspend an elinks session, and then try to resume it with ...
0
votes
1answer
146 views

When executing a command, it is automatically suspended

The problem happened on one of my local machines with CentOS 6. I ssh to it from my MacBook trying to test a script, which is in /usr/local/bin. However, whenever I tried to execute the command, it is ...