Hi All!

I have a script like the following:

ssh -f xyz@abc.def.edu "cd /home/xyz/ ; nohup java -Xmx1024m abc <ParamFile> & ; JAVAParent=$!; echo $JAVAParent >> parentPID.txt"

The script essentially runs a java program in the client machine abc.def.edu and outputs the PID of this process to a file. [We know $! holds the PID of the last spawned process. ]

However while running this script, I find that JAVAParent isn't holding any value. In fact while I debug this script using bash -x script.sh, I find that the line corresponding to JAVAParent=$! is shown as JAVAParent= ; (there is no $! here!).

I would be more than pleased if you could help!

Thanks in advance!

Hi.

The $! is being evaluated before being sent as part of the command line. Use hard (single) quotes around the command line to stop this. i.e.
ssh -f xyz@abc.def.edu 'cd /home/xyz/; nohup java -Xmx1024m abc <ParamFile> & JAVAParent=$!; echo $JAVAParent >> parentPID.txt'

Dave

Hi ilikejam!

Thanks for the reply. It is working now. But it seems the process is actually not running. That is,

ssh -f xyz@abc.def.edu 'cd /home/xyz/; nohup java -Xmx1024m abc <ParamFile> & JAVAParent=$!; echo $JAVAParent >> parentPID.txt'

I don't find the abc file running. Though the parentPID.txt has a Process id now, I don't find the process corresponding to it in top.

Why is that?

Looking forward to your help!

Wouldn't that depend on what it's meant to do, and how
long it ran for (is meant to run for)?

Hi Tinkster!

That program actually runs for hours! However I would like to have some other process run parallely in another client using the process id of this parent process. That is why, I made it nohup and ended it with &.

I would greatly appreciate any help as I have been stuck with this for two days now!

See if there's any clues in /home/xyz/nohup.out - the stdout and stderr from the java process should be in there.

Dave

Does the code actually work if you run it interactively?


Cheers,
Tink

Hey Dave!

The nohup.out file itself isn't created! What on earth is happening?!

Hey Tink!

Yes, the code doesn't work if I run interactively! I guess, the problem is actually with the use of $! . I am not sure... Please help!

But if I run the commands separately one by one, they do work!

Some one please help!

I noticed a ';' after the '&' in your first post - it shouldn't be there.

Dave

All!

I was able to find where the problem was. Note that the $<variableName> whenever is inside " ", should have a '' surrounding it!

This was the problem I had. I can't believe how crazy these mistakes can drive us!

Thanks for all your help!