I have a script that opens a program that can remain open for an indeterminate amount of time. What I would like to do, is have a cleanup command called upon exiting this program. It's a separate command that we're having our techs issue manually when they exit the program, however, they aren't always diligent.
Any suggestions on how I can accomplish this? Essentially they'd CTRL+C out or using the "X" button in the GUI. The terminal in which it was called (or my script ran) remains open. So far I haven't found anything that allows me to block on while a program is running when opened by that script.
Thanks!
You can use the trap command, which supports a fake signal called EXIT:
trap 'exitScript.sh' EXIT
This will execute exitScript.sh regardless of the reason for exit, including CTRL+C but not including a KILL (9) signal.
Related
I have the following code written in a script anmed test.csh to start a GUI based application in foreground in Solaris Unix. When I run the script and want to kill the GUI process using Keyboard Ctrl + C, the process is not getting terminated. If I open the GUI application directly from the terminal, I am able to kill the process using Ctrl + C. Can someone help me understand why am I not able to kill the process invoked from a script?
#! /usr/bin/csh
# some script to set env variables
# GUI Process
cast
Then I execute the script using the following command. I am not able to terminate the vcast process using Ctrl + C command.
source test.csh
If it is being launched into its own thread then the hangup request may not get to the application. You could add a signal handler to cascade the hangup request or look at the process table to see what the process id is for the app and then kill it. This could also be scripted very easily.
You should better execute the script directly, instead of sourcing it.
1) first add #!/bin/csh at the beginning of your script,
2) set it as executable :
$ chmod u+x test.csh
3) execute it directly:
$ ./test.csh
you should be able to kill it. Anyway, consider that the problem may be related to some executable code that you are running within your script. Consider to try to debug your script by copy-pasting line after line in a terminal until you reach the point where it lags.
Another possible annoying issue can be an infinite while loop. Check for this kind of error too. Maybe you have a while loop that never gets the breaking point.
Regards
Is there a way to pause a Bash script, then resume it another time, such as after the computer has been rebooted?
The only way to do that AFAIK:
Save any variables, or other script context information in a temporary file to establish the state of the script just before the pause. This goes without saying that the script should include a mechanism to check this file to know if the previous execution was paused and, if it was, fetch all the context and resume accordingly.
After reboot, manually run the script again, OR, have the script automatically run from your startup profile script.
Try Ctrl-Z to pause the command. I don't think you can pause it and then resume after reboot unless you're keeping state somehow.
You can't pause and resume the same script after a reboot, but a script could arrange to have another script run at some later time. For example, it could create an init script (or a cron job, or a login script, etc) which contained the tasks you want to defer, and then removed itself.
Intriguing...
You can suspend a job in BASH with a CTRL-Z, but you can't resume after a reboot. A reboot initializes the machine and the process that was suspended is terminated.
However, it might be possible to force the process into a coredump via a 'kill -QUIT $pidand then usegdb` to restart the script. I tried for a while, but was unable to do it. Maybe someone else can point out the way.
If this applies to your script and the job it does, add checkpoints to it - that means places where all the state of the process is saved to disk before continuing. Then have each individual part check if the output they have to produce is already there, and skip running if it is. That should make a rerun of the script almost as efficient as resuming from the exact same place in execution.
Alternatively, run the script in a VM. Freeze the VM before shutting down the real system and resume it afterwards. It would probably take a really huge and complex shell script to make this worth it, though.
I have a script that does some processing and then will call another relevant script. This second script may not be the same each time.
How do I call the second script from bash and have my first script wait until it is finished before it continues. I also want to run the second script in its own window.
Currently I have:
gnome-terminal -x sh second.sh
But the first script continues whilst second is running.
Your problem here is not with bash (which processes commands in sequence unless you explicitly tell it not to using &), it's with gnome-terminal, which hands off your execution request to a background process and then terminates the one you called.
As far as I can tell, there is no way to get gnome-terminal to behave differently. An alternative might be to use xterm, which is synchronous by default.
I want to run a shell command within ccl, but this command may be hung for some reason. So I want to kill all the sub process generated by this command. How can I do this?
I have tried trivial-shell to run the shell command, when the command not hung, it works well.
I also use with-timeout macro which is in trivial-shell to check the timeout, it just give me a timeout-error condition, the shell process is still hunging there. Here I just want to kill them all and return something.
Thank you all.
As far as I can tell, trivial-shell only provides a synchronous shell call so there's no simple way to terminate ongoing subprocesses.
I suggest calling Clozure Common Lisp's implementation-specific ccl:run-program function with :wait nil to run the jobs asynchronously. You can then call ccl:signal-external-process on the running process to kill it if you need. Documentation here.
I'm trying to run a script, which internally invokes other script
but, the main script should exit after invoking and the invoked script should run independently on the background.
How can i achieve this in shell scripting? or is there any other alternative way to do this?
Regrads,
senny
nohup otherscript &
The nohup will ensure that the process keeps running even if the current terminal goes away (for example if you close the window).
(Just to make it clear: the "&" puts the other script in the background, which means the first will keep running, and the second script won't exit when the first one does.)
If your script is in Perl, use exec() command to start the second script.
exec() returns immediately after executing the command, and the calling script can exit, while the second script keeps running.
http://perl.about.com/od/programmingperl/qt/perlexecsystem.htm