mjhjmtu

I've got this strange behaviour https://stackoverflow.com/q/46583758/2553194
but let me resume and refocus the problem:

I'm executing a java program launched using a shell script that goes like this:

#!/bin/bash
export PATH=.:$PATH

java -jar myJar.jar &

Inside my java code I execute this piped command

ntpq -c peers | awk ' $0 ~ /^*/ print $9'

in order to obtain the offset of the NTP synchronized server.

To execute a piped command inside a java program, I've to use the above mentioned line as an argument of /bin/sh. I execute /bin/sh not the piped command directly.

This is the equivalent that you can launch in a console [1]

/bin/sh -c 'ntpq -c peers | awk '"'"' $0 ~ /^*/ print $9'"'"''

Example output from ntpq

 remote refid st t when poll reach delay offset jitter
==============================================================================
*172.30.100.1 172.22.204.171 4 u 207 1024 377 1.490 53.388 49.372

Parsing it with awk, I obtain

53.388

Usually it goes well, but sometimes for reasons unknown [This is my question] my program stops working fine. It returns nothing when the execution of the piped command from the console returns a number.

Recovering the err from the executed process created by java, I've obtained this text

/bin/sh: ntpq: command not found

So, sometimes I can execute [1] from a java program and sometimes I can't. Something is happening in the SO behind the scene. Can someone enlighten me, please?

I originally posted a similar question in StackOverflow, thinking that the problem may be related with the java programming but it wasn't.

Finally we found what was happening.

My java program is launched with a shell script. When we execute the script manually, ntpq command is found and invoked successfully. The problem arises when the software is fully deployed. In the final environment we've got a cron scheduled demon that keeps our program alive but PATH established by cron is different from the PATH that our profile has got assigned.

PATH used by cron:

.:/usr/bin:/bin

PATH that we got login for launching the script manually:

/usr/sbin:/usr/bin:/bin:/sbin:/usr/lib:/usr/lib64:/local/users/nor:
/usr/local/bin:/usr/local/lib:.

Usually ntpq is in

/usr/sbin/ntpq

Here you can find a better description of the problem and various solutions.