[bash script] How to catch the return string?

thomas2004ch · 02-27-2012, 08:42 AM

Hi all,

I am not sure if this is the correct place for my question, but I couldn't find out anywhere so I try here. Maybe there is someone who can help.

I have a bash-script file used to start/stop the Jboss. I want to extend this script so that each time if one starts the Jboss it will check if a Jboss instance is already started. This will avoid double or multipul startup of Jboss.

I will use the folloing code to check the Jboss:

Code:

...
ps -ef | grep java | grep org.jboss.Main
...

If I got no hit, it means no Jboss is started. But how can I get the return string or return code?

Thomas

druuna · 02-27-2012, 08:51 AM

Hi,

$? gives you the exit status of the last command that is executed.

In general: 0 (zero) all is ok and >= 1 something went wrong.

grep specific:

Quote:

EXIT STATUS
The exit status is 0 if selected lines are found, and 1 if not found.
If an error occurred the exit status is 2. (Note: POSIX error handling
code should check for '2' or greater.)

The following will show the exit status:

Code:

...
ps -ef | grep java | grep org.jboss.Main
echo "$?"
...

to quit if already running:

Code:

...
ps -ef | grep java | grep org.jboss.Main
[[ "$?" == "0" ]] && echo "already running" && exit 255
...

Hope this helps.

thomas2004ch · 02-27-2012, 08:59 AM

Many thanks!

druuna · 02-27-2012, 09:06 AM

You're welcome

BTW: Can you put up the [SOLVED] tag.
first post -> Thread Tools -> Mark this thread as solved