Rescue errors in terminal launched from script - linux

I am using Ubuntu and made a short script on my Desktop. Double clicking it opens a terminal and starts my server.
This is all working fine except there's one problem. If there's an error raised in my server, the launched terminal immediately closes.
I want to keep the terminal open and show the error.
Here's my script:
#!/bin/bash
gnome-terminal -e '/bin/bash -c "cd ~/Desktop/browser_tester/; ./start.sh" '
I'm using the advice from this AskUbuntu answer to construct that command. I'm asking for a way to rescue errors inside the subprocess so that the gnome_terminal displays those errors and doesn't just exit.

You can check the exit status.
./start.sh || read
This will wait for a keypress if the command failed.

Related

Linux (Raspbian) - Running script at login(auto) and keeping window in foreground for interaction

I have tried everything to make this work. login scripts, LXDE-pi autostart, cron task #reboot, init.d, and I cannot get my script running with a terminal window running in the foreground so that I can interact with it. I can get it to run but only in background. Is there any way I can get a script that simply runs: "python /home/pi/myscript.py" at startup and leaves the terminal window open with the script running for my keyboard inputs? I would rather not use the /dev/input/event if at all possible. Thanks
Simply running python /home/pi/myscript.py at startup will run your script without any terminal. So there is no window that can be kept open. The behavior you want can be achieved by starting an terminal application and let it execute your script.
e. g. using xterm:
xterm -e "python /home/pi/myscript.py"
or lxterminal:
lxterminal --command "python /home/pi/myscript.py"
I was missing a simple flag.. what I did was edit ~/.config/lxsession/LXDE-pi/autostart with
#lxterminal -e /home/pi/autoscript.sh
and in that file, I added
cd /home/pi/
python -i 2Trackmain.py
I wasn't using the -i flag, so every time I pressed Enter to move through the interactive py script, it exited the terminal, using -i will keep the window open for your interaction. And I only had to add the change directory part b/c the script called other scripts in the same directory.

Close google chrome open in app mode via command line

In my python script I am opening chrome in app mode by this command:
google-chrome --app=http://stackoverflow.com
Now I want to be able to close only this running chrome application (I mean if there is another chrome windows with diffrent tabs I don't want to close that, only this that i run). Is this possible and how?
I am using linux.
EDIT:
As far i manage to do something like this:
import subprocess
proc = subprocess.Popen(['google-chrome',
'--user-data-dir=/home/chrome-user', 'http://google.pl'])
# do something
proc.terminate()
And when I call this python script from command line everything is ok. My problem starts when I am running this as a linux service (under /etc/init). I logged and everything is ok except that google chrome seems to not be able to create window or something? I mean there is no error but google chrome window doesn't shows at all.
EDIT 2:
Definitely it is a problem with startup. When i run this on startup:
mate-terminal -e "python3
/path/to/script/script.py"
Everything works fine except that terminal windows is shown. So this somehow solves my problem but if anyone will have got any sugestion what can i do i would highly apreciate it.
as far as I know chrome creates a new process for each tab, killing the process therefore would work. you can kill the process by PID and the PID can be retrieved like this right after starting the process: (in bash) echo $!
Ok so after a long time I come with answer. In linux mint you need to add this to startup programs:
mate-terminal -e "python3 /path/to/script/script.py"
and if you want to run script as root user, this is solution for it (it's very ugly, but works):
mate-terminal -e "bash -c 'echo pass | sudo -S python3 /path/to/script/script.py;$SHELL'"

Running a script in the background before logging in

I have a python script that I want run prior to any user logging in. This is for a home automation server and I want it always to be up and running as soon as the system allows.
I already have it in the rc.local file including an ampersand. This works.
But I can't see the screen output that it produces.
When I log into the unit (it's a raspberry pi running raspian) via SSH I can start it using screen which works the best as when I logout and back in, it's still there. AND I can see the output from the script.
But when I try running screen from the rc.local file, and subsequently login to check, the script isn't there (ie ps aux | grep script.py confirms)
edit: I've taken on Nirk's solution below about using tail. From the command line, it works fine. But starting it form within /etc/rc.local doesn't. I have touched the file and everyone has write access to it.
This is what's in my rc.local file:
python /home/pi/gateway.py &> /x10.log &
UPDATE
This is how I did it in the end:
Although the question was just about how to run in the background prior to login, there was more to it. The script is a work in progress and because of the way a particular serial device acts with it, it is/was prone to crashing (I've almost got all the bugs out of it). I needed to be able to restart it as well. I tried nohup but for some reason, it wouldn't keep it alive so in the end I found the top answer from this page got it all sorted.
In my /etc/rc.local I included a shell script to run:
nohup /home/pi/alwaysrun.sh > /home/pi/mha.log 2>&1 &
alwaysrun.sh contains:
#!/bin/bash
until python /home/pi/gateway.py; do
echo "'gateway.py' exited with exit code $?. Restarting..." >&2
sleep 1
done
nohup will keep the alwaysrun.sh script alive, and that in turn keeps my gateway.py script running. The redirect of stdout and stderr means I can setup a tail (and/or go back and check) the log.
Instead of using screen, if you just want to see the output you should redirect the output of the command to a log file and then tail the file.

Linux KDE Login Script

I've been trying to set up a server that I want to run when I log in (in case the computer crashes or anything like that).
The script works and it runs on log in but it runs in the background or something as when I use ps -A I can see the process running. This is ok but the server is interactive so I want it to start in a terminal window and keep that window open after the user is logged in so that commands can be issued to the server. Is there a way of doing this?
What about starting your script like:
xterm -e YOURSCRIPT
Or if you prefer to use KDE's konsole:
konsole -e YOURSCRIPT
Those open a terminal window to run the specified command after -e.
HTH

Tomcat script not working when run from Hudson

I'm trying to run a script which stops and starts Tomcat on linux.
When I run it from the command line it works fine. But it does not seem to work when I run the same script from the "Execute Shell" build step in a Jenkins/Hudson job. Jenkins doesn't report any errors but if I try going to the tomcat page then I get a page not found error.
So Jenkins seems able to stop the server, but not bringing it back up.
I'd be grateful for any help.
Try unsetting the BUILD_ID in your 'shell execute' block. You might even not need to use nohup in this case
BUILD_ID=
./your_hudson_script_that_starts_tomcat.sh
Without seeing your script it is difficult to give an exact answer. However you could try adding the following to the start of your script (assuming it is a bash script):
# Trace executed commands.
set -x
# Save stdout / stderr in files
exec >/tmp/my_script.stdout
exec 2>/tmp/my_script.stderr
You could also try adding
set -e
to make the shell exit immediately if a command returns an error status.
If it looks as though Hudson is killing off Tomcat then you might want to run it within nohup (if you're not already doing that):
nohup bin/startup.sh >/dev/null 2>&1 &

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