Java and Shell scripts

[Eric Chang]

So because the platform I'm developing a Java application for is Solaris, I need to be able to run a mount CD or USB script which is provided to me. The script will return a status code...so first question is, where do I start looking at to execute and get the status code of the script?
Second question is, if the status code is 0 (as in failure), the script will echo out some sort of meaningful error message. I would like to capture that and be able to display it in a error dialog...how would I go about capturing that.
Also (probably a little bit outside of this forum, but I'll give it a shot)...does the script run in a separate shell? Like if I have System.outs in my main program, and then run the script, will I have an issue capturing the echo outputs from the script?
Thanks!

[Eric Chang]

Here's the actual script (sorry, it's a bit long...but I'm not knowledgable enough with shell scripting to know what parts are important).

#!/bin/sh
################################################################################
#
# This script has two intentions.  First it can be used to mount and unmount 
# CDs in the attached drive.  Second it will create a link in the root directory
# which can be used as the device for mounting and un-mounting in the future
#
################################################################################
 
#set -x
 
device_list ()
{
 
DEVICES=`ls /dev/dsk | grep s0`
echo "${DEVICES}"
 
}
 
remove_cdrom0 ()
{
   if [ -d ${MOUNT_BASE} ]
   then
      for old_file in `ls -A ${MOUNT_BASE}`
      do
         rm -fr  ${MOUNT_BASE}/${old_file} 1> /dev/null 2>/dev/null
      done
 
      if [ ! -d ${MOUNT_POINT} ]
      then
         mkdir -p ${MOUNT_POINT}
      fi
   else
      mkdir -p ${MOUNT_POINT}
   fi
}
 
umount_cd ()
{
  MOUNTED=`df -k -F hsfs | awk '{print $6}' | grep -v Mounted`
  PWD=`pwd | cut -f2 -d\/`
  if [ "${PWD}." = "${MOUNT_POINT}." ]
  then
     echo "You cannot unmount the CD device while you are in the ${MOUNT_POINT} directory."
     exit 1
  fi
 
  if [ "${MOUNTED}." = "${MOUNT_POINT}." ]
  then
     umount ${MOUNT_POINT}
     STATUS=$?
     export STATUS
  elif [ "${MOUNTED}." != "." ]
  then
     AMNT=`df -k -F hsfs | awk '{print $6}' | grep -v Mounted`
     echo "A CD appears to be mounted at ${AMNT}"
     echo "Executing \"umount ${AMNT}\" to un-mount the CD before continuing"
       if [ "${PWD}." = "${AMNT}." ]
       then
           echo "You cannot unmount the CD device while you are in the ${AMNT} directory."
           exit 1
       else
           umount ${AMNT}
           STATUS=$?
           export STATUS
       fi 
  fi
}
 
mount_cd ()
{
umount_cd
remove_cdrom0
if [ -h ${DEVICE_LINK} ]
then
   mount -F hsfs ${DEVICE_LINK} ${MOUNT_POINT} 1>/dev/null 2>/dev/null
   if [ $? = 0 ]
   then
       echo "CD mounted on ${MOUNT_POINT}"
   else
       echo "CD was not mounted.  Please ensure there is a CD in the drive and try again."
       exit
   fi
else
   for x in `echo $POSSIBLES`
   do
     mount -F hsfs /dev/dsk/${x} ${MOUNT_POINT} 1>/dev/null 2>/dev/null
       if [ $? = 0 ]
       then
           echo "Mount Successful"
           echo "Creating link to device for future use...."
           ln -s /dev/dsk/${x} ${DEVICE_LINK}
           echo "CD mounted on ${MOUNT_POINT}"
           exit
       fi
   done
echo "No CD device found.  Please ensure that there is a CD in the drive and try again."
fi
}
 

 
################################################################################
#
# Start Here
#
################################################################################
 
POSSIBLES=`device_list`
MOUNT_BASE=/cdrom
MOUNT_POINT=/cdrom/cdrom0
DEVICE_LINK=/dev/dsk/CDROM_DEVICE
 
USAGE="USAGE: $0 [ -m (mount) ] [ -u (unmount) ] [ -p <mount-point> ]"
 
if [ "${1}." = "." ]
then
   echo "${USAGE}"
   exit 1
fi
 
MOUNT_CD="NO"
UMOUNT_CD="NO"
 
while getopts mup: MOUNT_OPTS
do
   case $MOUNT_OPTS in
            m ) MOUNT_CD="YES" ;;
            u ) UMOUNT_CD="YES" ;;
            p ) MOUNT_POINT=$OPTARG ;;
            * ) echo "$USAGE" ; exit 1 ;;
   esac
done
shift `expr $OPTIND - 1`
 
if [ "${MOUNT_CD}." = "YES." ]
then
   mount_cd
fi
 
if [ "${UMOUNT_CD}." = "YES." ]
then
 
   umount_cd
   if [ "${STATUS}". = "0". ]
   then
       echo "CD can now be removed......"
       exit
   else
       echo "CD could not be un-mounted."
   fi
fi
 

What puzzles me is that there does not seem to be any status or exit if the mount of the CD is successful or not which leads me to believe that there needs to be some work done on the script.
Nevertheless, if someone can decipher this stuff and help me out, it would be greatly appreciated.

[Norm Radder]

Look at the Process class. It will run a command and allow you to get its output with various methods.

The script looks like it returns a 0 on success and a 1 on failure.

[Eric Chang]

Excellent, thanks for pointing me in the right direction!

[Campbell Ritchie]

Originally posted by Norm Radder:
Look at the Process class.

More discussion about running Processes here, and in the associated links in that thread.