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 &
Related
I've found a very strange issue, when in linux terminal I type "enable -n trap", it would disable the trap linux builtin command. But if I put it into a script like
#!/bin/bash
enable -n trap
and then run the script, there's no error but the command is also not disabled. Really appreciate if someone could share what is happening and how to run it in some file instead of directly in the terminal. Thank you!
The enable command only affects the current shell. When you run a script, that script is executed in a new process, so:
A new shell starts
The enable command runs and disables the trap command in that shell
The shell exits
If you want to affect the current shell, your only option is to source the script using the . (or source) command. If the script is named disable-trap.sh and is in your $PATH, you can run:
. disable-trap.sh
You can also provide a full path to the script:
. /path/to/disable-trap.sh
Sourcing a script like this is largely equivalent to typing the same commands in at the command line: it executes the instructions in the script in the current shell, rather than spawning a new process.
I'm on ubuntu 17.04, and I'm trying to execute some commands in sequence, so I have written this shell script:
#!
sudo java -jar ~/Desktop/PlugtestServer.jar
sudo /opt/lampp/lampp start
sudo node httpServer.js
The problem is that after the first command, it execute PlugtestServer and then stop on it, because it is a server and continue to execute it. There is a command in order to automatically open a new terminal and execute PlutestServer in it?
There is way to open a new terminal window and execute command in it using gnome-terminal
The sample format for command is:
gnome-terminal -e "command you want to execute"
gnome-terminal -e "./your-script.sh arg1 arg2"
Hope that helps!!
Your script stays on the first command showing output, you can make the shell move on by adding "&" to the end of your lines. However this might still not do what you want, if you want PlugTestServer to remain running when you log out. For that you should include "nohup" which will keep the command running while piping output to a file.
So, an example:
#!/bin/sh
nohup java -jar ~/Desktop/PlugtestServer.jar > plugtest.out & #Pipes output to plugtest.out, use /dev/null if you don't care about output.
/opt/lampp/lampp start
node httpServer.js
Notice I removed sudo from the script. It's generally better to invoke the script with "sudo" unless you have specific reason to, at the very least it simplifies the commands.
I'm not sure if your second and third command "fork" or "block", so add "nohup" and "&" if you need to.
I am trying to schedule the execution of a shell-script with the Linux tool "at".
The shell script (video.sh) looks like this:
#!/bin/sh
/usr/bin/vlc /home/x/video.mkv
The "at" command:
at -f /home/x/video.sh -t 201411052225
When the time arrives, nothing happens.
I can execute the shell-script just fine via console or by rightclicking - Execute. VLC starts like it is supposed to. If I change the script to e.g. something simple like
#!/bin/sh
touch something.txt
it works just fine.
Any ideas, why "at" will not properly execute a script that starts a graphical program? How can I make it work?
You're trying to run an X command (a graphical program) at a scheduled time. This will be extremely difficult, and quite fragile, because the script won't have access to the X server.
At the very least, you will need to set DISPLAY to the right value, but even then, I suspect you will have issues with authorisation to use the X screen.
Try setting it to :0.0 and see if that works. But if you're logged out, or the screensaver's on, or any number of other things...
(Also, redirect vlc's stdout and stderr to a file so that you can see what went wrong.)
Your best bet might be to try something like xuserrun.
I suspect that atd is not running. You have to start the atd daemon before (and to set DISPLAY variable like chiastic-security said) ;)
You can test if atd is running with
pidof atd &>/dev/null && echo 'ATD started' || echo >&2 'ATD not started
Your vlc command should be :
DISPLAY=:0 /usr/bin/vlc /home/x/video.mkv
(Default display)
I have a short php utility script, I run it from cli simply with:
php myscript.php
The script is always running, periodically performing some tasks (not relevant for the question). It doesn't need any input from the user.
After running it, I usually press CTRL+z and then run bg to put the process in background, and everything is fine.
If I run it as:
php myscript.php &
the script is put on background on start, but it is also put in a stopped state. Example:
[1] 11513
[1]+ Stopped php myscript.php
even running bg at this point doesn't help, I have to run fg, then CTRL+z and bg again to make it work.
This is the php script:
<?
while(true){
echo 'hi '.time()."\n";
sleep(30);
}
?>
My problem is that I cannot run it directly in background, because the system stops it, and I don't understand why. How can I fix this?
update:
I made a bash version of the same script, and it can be run and put in background (running and not stopped) just by launching it with the & in the end (script.sh &)
script.sh:
#!/bin/bash
while true; do
echo `date`
sleep 30
done
Why the php script is being stopped after launching it in background, and the bash script doesn't?
What could cause this different behaviour?
I found what is causing the issue. In PHP, if the readline module is enabled, any command line script will expect an input, even if the script is written to NOT wait for user input.
To check if you have readline support enabled, just run:
php --info |grep "Readline Support"
and check the output. If you get Readline Support => enabled then you have readline enabled and you may experience the problem described in the original question.
The proper way to use the cli when is then to explicitly specify that php is not using the terminal for input:
php myscript.php < /dev/null &
Further info: http://php.net/manual/en/book.readline.php
Alternatives:
./test.php >/dev/null &
or (more creative):
nohup php test.php > /dev/null 2>&1 &
(p.s.: I still believe this question belongs to ServerFault, btw.. problem solved!)
Usually, the process what do you send to background with the & and the script waiting for an input from the terminal, going into the stopped state.
E.g. have a bash script valecho:
#!/bin/sh
read val
echo $val
runnig it as:
./valecho &
the script will stop.
When run it as
echo hello | ./valecho &
will correctly run and finish.
So, check your php - probably wants some input from the stdin
Edit - based on comment:
i'm not an php developer - but just tried the next script (p.php)
<?php
while(true){
echo 'hi '.time()."\n";
sleep(3);
}
?>
with the command:
php -f p.php &
and running nicely... so... sry for confusion...
From http://php.net/manual/en/book.readline.php :
When readline is enabled, php switches the terminal mode to accept line-buffered input. This means that the proper way to use the cli when you pipe to an interactive command is to explicitly specify that php is not using the terminal for input:
php myscript.php < /dev/null &
source
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.