I have a Java program that spawns a bash script that calls another script. In that second script, I'm finding that the $HOME variable is not set. Here's the gist of it:
In Java:
Process p = new ProcessBuilder("bash", "-l", "/foo/a.sh").start();
// code to actually execute p
/foo/a.sh:
#!/bin/bash
/foo/b.sh
/foo/b.sh:
#!/bin/bash
echo "HOME=$HOME"
This echoes "HOME=". The eventual problem is that $HOME/bin is supposed to be added to my PATH in ~/.profile, but since that's not happening, a bunch of custom executables aren't being made accessible.
I worked around it by doing:
if [ -d ~/bin ] ; then
PATH=~/bin:"$PATH"
fi
And that works fine. But I guess I just want to understand why $HOME wasn't being set. It seems like $HOME and ~ should be largely equivalent, no? There's probably something I'm fundamentally missing about how this environment is getting set up.
I am running Ubuntu 12.04.5, if that makes a difference.
The evidence suggests that HOME is missing from the environment in which the Java app is running. Assuming that the app doesn't explicit unset HOME, the most likely reason is that the app is being started from some context other than a login by the user the app is running as.
It's correct that ~ and $HOME are similar. If HOME is present in the environment, even if it is set to the empty string, ~ will be replaced with $HOME. However, if HOME is not present in the environment, bash will attempt to find the home directory for the currently logged in user, and use that for ~.
eg.
$ bash -c 'echo ~'
/home/rici
$ HOME='Hello, world!' bash -c 'echo ~'
Hello, world!
$ HOME= bash -c 'echo ~'
$ (unset HOME; bash -c 'echo ~';)
/home/rici
Since your workaround requires the equivalent of the last scenario, I conclude that HOME has not been set, or has been unset.
Related
I've spent the past couple days working on this, and at this point I am super stuck. I have a Java program that must be run not as a service. This program must also be capable of updating itself when a new file is given for updating.
As a result, I have a script that is started with Linux that starts the Java application and then checks every 5 seconds if the application has been terminated. If the application has been terminated, it should check if there is an update and then start appropriately.
This is the code for that script:
#!/bin/bash
JAVA_HOME=/usr/lib/jvm/java-16-openjdk-amd64
WORKING_DIR=~/Data
LOG=$WORKING_DIR/logs/Bash.log
rm $LOG
echo "Script started" > $LOG
while true; do
source $WORKING_DIR/Server.pid
if ! kill -0 $AppPID; then
echo "App must be started" >> $LOG
source $WORKING_DIR/UpdateStatus
if [ "$UpdateReady" -eq "1" ]; then
echo "Moving files for update" >> $LOG
mv $WORKING_DIR/Server.jar $WORKING_DIR/old.jar
mv $WORKING_DIR/new.jar $WORKING_DIR/Server.jar
fi
nohup ${JAVA_HOME}/bin/java -jar ${WORKING_DIR}/Server.jar &
echo AppPID="$!" > $WORKING_DIR/Server.pid
echo "Server started" >> $LOG
if [ "$UpdateReady" -eq "1" ]; then
echo "Checking for safe update" >> $LOG
source $WORKING_DIR/Server.pid
echo UpdateReady="0" > $WORKING_DIR/UpdateStatus
sleep 5;
if kill -0 $AppPID; then
echo "Update successful" >> $LOG
rm $WORKING_DIR/old.jar
else
echo "Update failed, restarting old jar" >> $LOG
rm $WORKING_DIR/Server.jar
mv $WORKING_DIR/old.jar $WORKING_DIR/Server.jar
nohup ${JAVA_HOME}/bin/java -jar ${WORKING_DIR}/Server.jar &
echo AppPID="$!" > $WORKING_DIR/Server.pid
fi
fi
echo "Server start process finished, going into idle state" >> $LOG
fi
sleep 5
echo "5 seconds idle passed" >> $LOG
done
To initialize the update, I have tried a couple of different things, both with the same result. First I had set UpdateReady="1" through Java, then used exit(0);. I have also tried having Java call a Bash script which also sets UpdateReady="1" but uses kill $AppPID to shutdown the java application.
The result is that both the Java application and the Bash script stop executing causing the update and restart to fail! I have looked through a significant amount of Stack Overflow questions and answers finding things such as nohup, all to no avail.
I will once again state that the Java application cannot be run as a service. No packages other than what is included in Java or made by Apache can be used, and no programs can be installed to Linux. I would prefer to solve the problem with Bash.
Upon testing some things mentioned in comments, I may have missed something that turns out to be important. While all other runs of the startup script will be run by the startup applications manager, the initial run is not.
The install is taken care of remotely with an SSH connection sending the following command string:
cd /home/UserName; unzip -u -o Server.zip; chmod 777 install.sh; bash install.sh &; exit
install.sh is as follows:
#!/bin/bash
INSTALL_DIR=~/Data
mkdir ${INSTALL_DIR}
mkdir ${INSTALL_DIR}/logs
mkdir ${INSTALL_DIR}/data
cp Server.jar ${INSTALL_DIR}/Server.jar
cp service-start.sh ${INSTALL_DIR}/service-start.sh
chmod 777 ${INSTALL_DIR}/service-start.sh
rm Server.jar
rm service-start.sh
rm Server.zip
nohup bash $INSTALL_DIR/service-start.sh &
Upon rebooting my machine, I noticed that this problem goes away! This means that there must be a problem with the initial setup script. When the shell command is run, it does seem to be sticky and not actually let go after the bash install.sh &. I have tried putting nohup at the beginning of this, however the entire line will not run in that case for reasons I am not able to determine.
I would prefer to not have the user be forced to restart after install and can't seem to find any way to force the Startup Application manager to start an application at any time other than startup.
Well, after a lot of searching and some prompting from the comments, I found that the issue lied with how the program was initially being started.
As mentioned in the update, the first run is always started by an ssh connection. I knew there was a slight problem with this ssh connection, as it seemed to hold onto the connection no matter what I did. It turns out that this was causing the problem that resulted in the Bash instance and the Java instance remaining attached.
The solution for this problem was found here: jsch ChannelExec run a .sh script with nohup "lose" some commands
After managing to get the initial setup to start with nohup properly, the issue has gone away.
I want to open Matlab without cd /usr/local/MATLAB/R2015b/bin and the sudo ./matlab.
So I sudo gedit ~/.bashrc and write the following commands in the ending:
export MATLAB_ROOT="/usr/local/MATLAB/R2015b/bin"
if [ -d "${MATLAB_ROOT}" ]; then
export PATH="${PATH}:${MATLAB_ROOT}"
fi
After source ~/.bashrc and I use echo $PATH to see that the path of matlab does exist. But when I use matlab to open the it, it will be stuck at Picked up JAVA_TOOL_OPTIONS: whereas cd /usr/local/MATLAB/R2015b/bin and the sudo ./matlab commands work well.
And if I directly use sudo ./matlab, it will show sudo：./matlab: command not found
Other information: which java shows /usr/bin/java
unset JAVA_TOOL_OPTIONS will cause another error.
Oh, I found the problem, I use the command JAVA_TOOL_OPTIONS=/usr/local/MATLAB/R2015b/bin or unset JAVA_TOOL_OPTIONS, and then get the error as follows.
It makes me recall the sudo command, so it might be a problem of permission right. Since I have to open Matlab without leaving that directory, I use ln -s /usr/local/MATLAB/R2015b/bin/matlab /path/to/your/current and then sudo ./matlab. It works.
But how to really solve this problem remains unknown. The other methods I saw like sudo apt-get remove jayatana and sudo rm /usr/share/upstart/sessions/jayatana.conf may cause unpredictable result, so I could not try them.
im working on distributed systems and my program is complete, i have tested it and it runs fine over 10 machines, but every time i want to test the program i have to:
- Copy the file for each machine
- ssh to each machine and type "java -jar file"
To avoid that painfull process I made this
for i in {1..11}
do
if [ $i -ne 6 ];
then
sshpass -p "qwerty" scp myJar.jar user#l040101-ws$i.XXXX.XX.XX:someFolder;
sshpass -p "qwerty" ssh user#l040101-ws$i.XXXX.XX.XX "java -jar someFolder/myJar.jar &" &
fi
done
And for some reason it doesnt work like it should, the scp command executes as it should, but the other one doesnt.
The program should produce a folder with 2 logs inside and if i do it manually it does, so i guess is not permission problem, but not with the script.
The weired thing is if i run top, i can see the java processes running in each machine.
BTW: those 2 & is so it the script doesnt get stuck after running each jar
I recommend using SSH keys rather than expressing the password in a command (which gets logged and is visible to other users, not to mention its presence in your script). The github ssh key generation docs are pretty good for this (to add, append to the server's ~/.ssh/authorized_keys file).
Once you have generated a key on the client and added its pubkey to the server, you should be able to run:
for i in {1..11}
do
if [ $i -ne 6 ] # skip server six
then
cat myJar.jar |ssh user#l040101-ws$i.XXXX.XX.XX \
"cd someFolder; cat > myJar.jar; java -jar myJar.jar" &
fi
done
Note the single ampersand there, which is outside the quotes (so it is run on your client, not your server). You can't send an SSH session to the background because the parent would be killed.
I wrangled this into one line in order to minimize the number of connections (the first cat command dumps the file into standard output while the second cat command writes the standard input (the contents of myJar.jar) to the target location). I wasn't sure if I could just pipe it straight to java (cat myJar.jar |ssh user#host "cd someFolder; java -jar -"), so I left that alone.
I'm assuming you don't have to run the .jar from the parent of someFolder. It seems simpler to actually be in the target directory. If there's a chance the target directory does not exist, add mkdir -p someFolder; before the cd command. The -p will ensure nothing happens if the directory already exists. If you do have to run it from the parent, remove the cd command and replace "myJar.jar" with "someFolder/myJar.jar"
I have a bash script on a Linux box that runs a Jar file. When logged in as a regular user I don't have permission to run the script, but it prints the following log:
*INFO * Using JVM found at /opt/jdk6/bin/java
When I try to use the script with Sudo though, it gives:
*ERROR* Unable to locate java, please make sure java is installed and JAVA_HOME set
I've set JAVA_HOME to the same path above — can see it with echo $JAVA_HOME & it's also set as an option within the script. I'm happy that the script isn't the issue — it's a default CQ5 control script & I'm using it on dozens of other boxes without issue. Just unsure what I'm doing wrong above & presume it's something I'm missing re Linux set-up?
When I run the sudo command, does it have access to the JAVA_HOME that I set up as myself?
By default, sudo will cleanup the environment of the spawned commands. Pass -E to keep it:
sudo -E env
Compare to:
sudo env
"sudo -E " didn't solve the problem when JAVA_HOME was not exported. And when it was exported, "sudo " without -E works the same.
So you can add export JAVA_HOME=.../jdk<version> in your .bash_profile and .bashrc file.
In case you wondered what's the difference of .bash_profile and .bashrc, .bash_profile is executed upon login (e.g., show some diagnostic/welcome information). .bash_rc is executed when you open a new terminal (e.g., shift-ctrl-T).
In order to run some commands for both cases, you can put it in .bashrc file, and let .bash_profile source .bashrc:
if [ -f ~/.bashrc ]; then
source ~/.bashrc
fi
You could always just pass it to java explicitly like this:
sudo java -Djava.home=$JAVA_HOME Test
I'm having a heck of a time getting a java program to launch properly in an init script using start-stop-daemon. I've written the init script and it seems to run but there's never a process afterward representing the running program.
Here's a snippet of my init script
#! /bin/sh
#
#
DAEMON="/usr/bin/java"
DAEMON_ARGS="-server -cp <bunch of RMI arguments and classpath stuff> -jar <absolute path>/myprog.jar"
PIDFILE="/var/run/myprog.pid"
case "$1" in
start)
echo -n "Starting myprog"
start-stop-daemon --start --pidfile "$PIDFILE" --chuid "myuser" --verbose --background --make-pidfile --startas "$DAEMON" -- $DAEMON_ARGS
echo "."
;;
When I try to launch it via /etc/init.d I get the following:
/etc/init.d# /etc/init.d/myscript start
Starting myprogStarting /usr/bin/java...
Detatching to start /usr/bin/java...done.
.
Afterward, there is no java interpreter process running, executing myprog.jar
I've tried various combinations of --exec, --start with more or less the same results. If I could get some more visibility into what is going on, I'm sure I could figure this out but I'm not sure how to do even that.
Any suggestions?
(I'm running Angstrom on an embedded ARM platform so Java Service Wrapper isn't really an viable option, ie. I don't think its available for ARM)
I'm stuck so any advice would be really appreciated.
Thanks.
Two things to try, first try removing --startas and use --exec instead like so:
start-stop-daemon --start --pidfile "$PIDFILE" --chuid "myuser" --verbose --background --make-pidfile --exec "$DAEMON" -- $DAEMON_ARGS
Second since you are using --background try specifying the --chdir option, if you don't the working directory ends up being /.
I ended up stumbling on your question trying to solve my issue which eventually was resolved by --chdir, I believe it will resolve yours as well.
you're looking for a way to run and be able to monitor it?
have you tried ms batch dos programming it yet?
for example
#echo off
cd DirectoryOfFiles
echo "Starting up..."
java -Xmx512m mainFile
pause
mainFile = main.java?
DirectoryOfFiles = the directory you have all the class files in, if running file is same directory just remove this line
hopefully this is what you're asking for