################################################################################
# 
# File:        switch
# Purpose:     Change ORACLE_SID environment variable
# Used by:     manual
# Remark:      Call with '. switch' otherwise your interactive shell's 
#              environment will not change!! (of course you can make 
#              an alias for '. switch' which may even be called 'switch'...)
# Author:      Gert de Boer
# Date:        19.03.2001
# 
# Change history:
# Who      when       what
# -------- ---------- ----------------------------------------------------------
#
################################################################################

# Loop through the instances mentioned in /etc/oratab, and take the next 
# one cyclically.

# Set start parameters:
do_nothing=0
sid_found=0

# Generate list of active Oracle instances:
oralist=$(grep -v '^#' /etc/oratab|grep ':Y$'|cut -d\: -f1)

# Double it, in order to go back to the first instance in the list
# if the last one is the actual one:
oralist="$oralist $oralist"

for sid in $oralist
do
   # I presume the previous one is the active one...
   if [ $sid_found = 1 ]
   then
      # If switched already, do not switch anymore:
      if [ $do_nothing = 0 ]
      then
	 # Otherwise, switch:
         export ORACLE_SID=$sid
	 echo 
	 echo ---------------------------------
         echo Oracle instance is set to $sid
	 echo ---------------------------------
	 echo 
	 # and do not ever switch again...
	 do_nothing=1
      fi
   fi
   
   if [ $ORACLE_SID = $sid ]
   then
      # Prepare for switching:
      sid_found=1
   fi

done