Unix Shell Script -- ORA-00905 error in pl/sql

Question

Below is my unix shell script .... in which i am trying to caluclate difference between time stamps ..... i am getting a severe error when i run --- ORA-00905: missing keyword ( included it bottom of this post )
please look into this and let me know where to correct ....
much appreciated in adv
~~~~~~~~~~~~~~~~~~~~~START of Script~~~~~~~~~~~~~~~~~~~~
#!/bin/ksh
export readTime checkTime timeDiff
# Get initial Time
readTime=`sqlplus -s scott/tiger@database <<EOF
whenever sqlerror exit 1
set escape off
set head off
set verify off
select SYSTIMESTAMP from dual;
EOF
`
echo "readTime value is : $readTime"
# Get end of time
checkTime=`sqlplus -s scott/tiger@database <<EOF
whenever sqlerror exit 1
set escape off
set head off
set verify off
select SYSTIMESTAMP from dual;
EOF
`
echo "value of checkTime : $checkTime"
# calculate time diff
timeDiff=`sqlplus -s scott/tiger@database <<EOF
whenever sqlerror exit 1
set escape off
set head off
set verify off
select CAST(TO_DATE('$time2','''YYYY\/MM\/DD:HH24:MI:SS'''))-CAST(TO_DATE('$VAR1','YYYY-MM-DD:HH24:MI:SS')) from dual;
EOF
`
echo "value of timeDiff : $timeDiff"
~~~~~~~~~~~~~~~~~OUTPUT here ~~~~~~~~~~~~~~~~~~~~~~~
readTime value is :
02-DEC-05 12.07.53.779328 AM -06:00
value of checkTime :
02-DEC-05 12.07.54.013613 AM -06:00
value of timeDiff : 02-DEC-05 12.07.54.013613 AM -06:00','''YYYY\/MM\/DD:HH24:MI:SS'''))-CAST(TO_DATE('
ERROR at line 2:
ORA-00905: missing keyword

Answer 1

You didn't specify if you want a total time for a portion of a shell script, or the whole script in general. If you only want to know the time of the whole shell script, just reference the linux/unix built-in variable ${SECONDS}. This variable is reset for each PID.
I usually add these lines to the bottom of long running shell scripts (just before an exit code):
~~~~~~~~~~~~~~~~~~~~~~~~~
((TIME = ${SECONDS} / 60))
echo "Script ran for ${TIME} minutes. (${SECONDS} seconds total.)
~~~~~~~~~~~~~~~~~~~~~~~~~
Like I said, ${SECONDS} starts ticking from 0 when you start the script, so no need to export the variable, just reference it. The nice part is that you don't have to bother getting into sqlplus and hit the database.